diff --git a/vcf/parser.py b/vcf/parser.py
index c3c3d082..e454ea41 100644
--- a/vcf/parser.py
+++ b/vcf/parser.py
@@ -275,7 +275,7 @@ def __init__(self, fsock=None, filename=None, compressed=None, prepend_chr=False
             self._separator = '\t| +'
 
         self._row_pattern = re.compile(self._separator)
-        self._alt_pattern = re.compile('[\[\]]')
+        self._alt_pattern = re.compile(r'[\[\]]')
 
         self.reader = (line.strip() for line in self._reader if line.strip())
 
@@ -533,7 +533,7 @@ def _parse_alt(self, str):
                 withinMainAssembly = True
             pos = remoteCoords[1]
             orientation = (str[0] == '[' or str[0] == ']')
-            remoteOrientation = (re.search('\[', str) is not None)
+            remoteOrientation = (re.search(r'\[', str) is not None)
             if orientation:
                 connectingSequence = items[2]
             else: