diff --git a/crates/oracle/src/chain_validation.rs b/crates/oracle/src/chain_validation.rs
new file mode 100644
index 00000000..4ea2f489
--- /dev/null
+++ b/crates/oracle/src/chain_validation.rs
@@ -0,0 +1,252 @@
+use crate::config::{IndexedChain, ProtocolChain};
+use crate::runner::jrpc_utils::JrpcExpBackoff;
+use crate::{Caip2ChainId, Config};
+use anyhow::anyhow;
+use std::str::FromStr;
+use tracing::{error, info};
+use web3::api::Web3;
+use web3::helpers::CallFuture;
+
+/// Validates that all configured RPC endpoints return the expected chain ID
+pub async fn validate_chain_ids(config: &Config) -> anyhow::Result<()> {
+    info!("Validating RPC chain IDs...");
+
+    // Validate protocol chain
+    validate_protocol_chain(&config.protocol_chain).await?;
+
+    // Validate indexed chains
+    for chain in &config.indexed_chains {
+        validate_indexed_chain(chain).await?;
+    }
+
+    info!("All RPC chain IDs validated successfully");
+    Ok(())
+}
+
+async fn validate_protocol_chain(chain: &ProtocolChain) -> anyhow::Result<()> {
+    let transport = JrpcExpBackoff::http(
+        chain.jrpc_url.clone(),
+        chain.id.clone(),
+        std::time::Duration::from_secs(30),
+    );
+    let web3 = Web3::new(transport);
+
+    validate_chain_id(&web3, &chain.id, chain.jrpc_url.as_ref()).await
+}
+
+async fn validate_indexed_chain(chain: &IndexedChain) -> anyhow::Result<()> {
+    let transport = JrpcExpBackoff::http(
+        chain.jrpc_url.clone(),
+        chain.id.clone(),
+        std::time::Duration::from_secs(30),
+    );
+    let web3 = Web3::new(transport);
+
+    validate_chain_id(&web3, &chain.id, chain.jrpc_url.as_ref()).await
+}
+
+async fn validate_chain_id<T>(
+    web3: &Web3<T>,
+    expected_chain: &Caip2ChainId,
+    rpc_url: &str,
+) -> anyhow::Result<()>
+where
+    T: web3::Transport,
+{
+    // Only validate EVM chains (namespace "eip155")
+    if expected_chain.namespace_part() != "eip155" {
+        info!(
+            "Skipping chain ID validation for non-EVM chain: {}",
+            expected_chain
+        );
+        return Ok(());
+    }
+
+    // Parse expected numeric chain ID from CAIP-2 reference
+    let expected_numeric_id = u64::from_str(expected_chain.reference_part())
+        .map_err(|e| anyhow!("Failed to parse chain ID from {}: {}", expected_chain, e))?;
+
+    // Call eth_chainId
+    let fut = web3.transport().execute("eth_chainId", vec![]);
+    let call_fut: CallFuture<String, T::Out> = CallFuture::new(fut);
+
+    let chain_id_hex = match call_fut.await {
+        Ok(id) => id,
+        Err(e) => {
+            error!("Failed to get chain ID from RPC {}: {}", rpc_url, e);
+            return Err(anyhow!(
+                "Failed to get chain ID from RPC {}: {}",
+                rpc_url,
+                e
+            ));
+        }
+    };
+
+    // Parse hex chain ID (e.g., "0xa4b1" -> 42161)
+    let actual_chain_id = u64::from_str_radix(chain_id_hex.trim_start_matches("0x"), 16)
+        .map_err(|e| anyhow!("Failed to parse chain ID hex '{}': {}", chain_id_hex, e))?;
+
+    // Compare
+    if actual_chain_id != expected_numeric_id {
+        error!(
+            "Chain ID mismatch for {}: RPC {} returned chain ID {} (0x{:x}), expected {} from CAIP-2 identifier {}",
+            expected_chain, rpc_url, actual_chain_id, actual_chain_id, expected_numeric_id, expected_chain
+        );
+        return Err(anyhow!(
+            "Chain ID mismatch for {}: RPC {} returned chain ID {} (0x{:x}), expected {} from CAIP-2 identifier {}",
+            expected_chain, rpc_url, actual_chain_id, actual_chain_id, expected_numeric_id, expected_chain
+        ));
+    }
+
+    info!(
+        "✓ Chain ID validated for {}: RPC {} correctly returns chain ID {}",
+        expected_chain, rpc_url, actual_chain_id
+    );
+
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use jsonrpc_core::{Call, Value};
+    use std::future::Future;
+    use std::pin::Pin;
+    use web3::RequestId;
+
+    #[test]
+    fn test_caip2_parsing() {
+        let chain_id = Caip2ChainId::from_str("eip155:1").unwrap();
+        assert_eq!(chain_id.namespace_part(), "eip155");
+        assert_eq!(chain_id.reference_part(), "1");
+
+        let chain_id = Caip2ChainId::from_str("eip155:42161").unwrap();
+        assert_eq!(chain_id.namespace_part(), "eip155");
+        assert_eq!(chain_id.reference_part(), "42161");
+
+        // Non-EVM chain
+        let chain_id = Caip2ChainId::from_str("bip122:000000000019d6689c085ae165831e93").unwrap();
+        assert_eq!(chain_id.namespace_part(), "bip122");
+        assert_eq!(
+            chain_id.reference_part(),
+            "000000000019d6689c085ae165831e93"
+        );
+    }
+
+    // Mock transport that returns a predefined chain ID
+    #[derive(Debug, Clone)]
+    struct MockTransport {
+        chain_id_response: String,
+    }
+
+    impl web3::Transport for MockTransport {
+        type Out = Pin<Box<dyn Future<Output = Result<Value, web3::Error>>>>;
+
+        fn prepare(&self, method: &str, params: Vec<Value>) -> (RequestId, Call) {
+            let call = Call::MethodCall(jsonrpc_core::MethodCall {
+                jsonrpc: Some(jsonrpc_core::Version::V2),
+                method: method.to_string(),
+                params: jsonrpc_core::Params::Array(params),
+                id: jsonrpc_core::Id::Num(1),
+            });
+            (1, call)
+        }
+
+        fn send(&self, _id: RequestId, request: Call) -> Self::Out {
+            let response = match request {
+                Call::MethodCall(ref call) if call.method == "eth_chainId" => {
+                    Ok(Value::String(self.chain_id_response.clone()))
+                }
+                Call::MethodCall(ref call) => Err(web3::Error::Decoder(format!(
+                    "Unexpected method: {}",
+                    call.method
+                ))),
+                _ => Err(web3::Error::Decoder("Invalid request type".to_string())),
+            };
+
+            Box::pin(futures::future::ready(response))
+        }
+    }
+
+    #[tokio::test]
+    async fn test_validate_chain_id_success() {
+        let mock_transport = MockTransport {
+            chain_id_response: "0x1".to_string(),
+        };
+        let web3 = Web3::new(mock_transport);
+        let chain_id = Caip2ChainId::from_str("eip155:1").unwrap();
+
+        let result = validate_chain_id(&web3, &chain_id, "http://test.com").await;
+        assert!(result.is_ok());
+    }
+
+    #[tokio::test]
+    async fn test_validate_chain_id_mismatch() {
+        let mock_transport = MockTransport {
+            chain_id_response: "0x1".to_string(), // Returns mainnet (1)
+        };
+        let web3 = Web3::new(mock_transport);
+        let chain_id = Caip2ChainId::from_str("eip155:42161").unwrap(); // Expects Arbitrum (42161)
+
+        let result = validate_chain_id(&web3, &chain_id, "http://test.com").await;
+        assert!(result.is_err());
+        let err_msg = result.unwrap_err().to_string();
+        assert!(err_msg.contains("Chain ID mismatch"));
+        assert!(err_msg.contains("returned chain ID 1"));
+        assert!(err_msg.contains("expected 42161"));
+    }
+
+    #[tokio::test]
+    async fn test_validate_chain_id_hex_variations() {
+        // Test with different hex formats
+        let test_cases = vec![
+            ("0x1", 1),             // 0x1
+            ("0x01", 1),            // 0x01
+            ("0xa4b1", 42161),      // 0xa4b1 (Arbitrum)
+            ("0xaa36a7", 11155111), // Sepolia
+        ];
+
+        for (hex_response, expected_id) in test_cases {
+            let mock_transport = MockTransport {
+                chain_id_response: hex_response.to_string(),
+            };
+            let web3 = Web3::new(mock_transport);
+            let chain_id = Caip2ChainId::from_str(&format!("eip155:{}", expected_id)).unwrap();
+
+            let result = validate_chain_id(&web3, &chain_id, "http://test.com").await;
+            assert!(
+                result.is_ok(),
+                "Failed for hex {} expecting {}",
+                hex_response,
+                expected_id
+            );
+        }
+    }
+
+    #[tokio::test]
+    async fn test_validate_chain_id_skips_non_evm() {
+        // Non-EVM chains should be skipped
+        let mock_transport = MockTransport {
+            chain_id_response: "should_not_be_called".to_string(),
+        };
+        let web3 = Web3::new(mock_transport);
+        let chain_id = Caip2ChainId::from_str("bip122:000000000019d6689c085ae165831e93").unwrap();
+
+        let result = validate_chain_id(&web3, &chain_id, "http://test.com").await;
+        assert!(result.is_ok());
+    }
+
+    #[tokio::test]
+    async fn test_validate_chain_id_invalid_hex() {
+        let mock_transport = MockTransport {
+            chain_id_response: "invalid_hex".to_string(),
+        };
+        let web3 = Web3::new(mock_transport);
+        let chain_id = Caip2ChainId::from_str("eip155:1").unwrap();
+
+        let result = validate_chain_id(&web3, &chain_id, "http://test.com").await;
+        assert!(result.is_err());
+        let err_msg = result.unwrap_err().to_string();
+        assert!(err_msg.contains("Failed to parse chain ID hex"));
+    }
+}
diff --git a/crates/oracle/src/main.rs b/crates/oracle/src/main.rs
index ca935dae..28459dfc 100644
--- a/crates/oracle/src/main.rs
+++ b/crates/oracle/src/main.rs
@@ -1,3 +1,4 @@
+pub mod chain_validation;
 pub mod commands;
 pub mod config;
 pub mod contracts;
diff --git a/crates/oracle/src/runner/mod.rs b/crates/oracle/src/runner/mod.rs
index b8c458d5..c3d07685 100644
--- a/crates/oracle/src/runner/mod.rs
+++ b/crates/oracle/src/runner/mod.rs
@@ -71,6 +71,14 @@ pub async fn run(config_file: impl AsRef<Path>) -> Result<(), Error> {
     init_logging(config.log_level);
     info!(log_level = %config.log_level, "The block oracle is starting.");
 
+    // Validate RPC chain IDs before starting
+    if let Err(err) = crate::chain_validation::validate_chain_ids(&config).await {
+        error!("Chain ID validation failed: {}", err);
+        return Err(Error::BadJrpcProtocolChain(web3::Error::Decoder(
+            err.to_string(),
+        )));
+    }
+
     // Spawn the metrics server
     tokio::spawn(metrics_server(&METRICS, config.metrics_port));