diff --git a/jedi/api/classes.py b/jedi/api/classes.py
index 4168f6e9..47cc7a07 100644
--- a/jedi/api/classes.py
+++ b/jedi/api/classes.py
@@ -536,9 +536,9 @@ class Definition(BaseDefinition):
         # here.
         txt = definition.get_code(include_prefix=False)
         # Delete comments:
-        txt = re.sub('#[^\n]+\n', ' ', txt)
+        txt = re.sub(r'#[^\n]+\n', ' ', txt)
         # Delete multi spaces/newlines
-        txt = re.sub('\s+', ' ', txt).strip()
+        txt = re.sub(r'\s+', ' ', txt).strip()
         return txt
 
     @property
diff --git a/jedi/evaluate/docstrings.py b/jedi/evaluate/docstrings.py
index 86b56673..6fac8b9f 100644
--- a/jedi/evaluate/docstrings.py
+++ b/jedi/evaluate/docstrings.py
@@ -68,7 +68,7 @@ def _search_param_in_numpydocstr(docstr, param_str):
         return []
     for p_name, p_type, p_descr in params:
         if p_name == param_str:
-            m = re.match('([^,]+(,[^,]+)*?)(,[ ]*optional)?$', p_type)
+            m = re.match(r'([^,]+(,[^,]+)*?)(,[ ]*optional)?$', p_type)
             if m:
                 p_type = m.group(1)
             return list(_expand_typestr(p_type))
@@ -103,11 +103,11 @@ def _expand_typestr(type_str):
     Attempts to interpret the possible types in `type_str`
     """
     # Check if alternative types are specified with 'or'
-    if re.search('\\bor\\b', type_str):
+    if re.search(r'\bor\b', type_str):
         for t in type_str.split('or'):
             yield t.split('of')[0].strip()
     # Check if like "list of `type`" and set type to list
-    elif re.search('\\bof\\b', type_str):
+    elif re.search(r'\bof\b', type_str):
         yield type_str.split('of')[0]
     # Check if type has is a set of valid literal values eg: {'C', 'F', 'A'}
     elif type_str.startswith('{'):
@@ -194,7 +194,7 @@ def _evaluate_for_statement_string(module_context, string):
     if string is None:
         return []
 
-    for element in re.findall('((?:\w+\.)*\w+)\.', string):
+    for element in re.findall(r'((?:\w+\.)*\w+)\.', string):
         # Try to import module part in dotted name.
         # (e.g., 'threading' in 'threading.Thread').
         string = 'import %s\n' % element + string
diff --git a/jedi/evaluate/helpers.py b/jedi/evaluate/helpers.py
index 5d3f39d2..c94a1fbe 100644
--- a/jedi/evaluate/helpers.py
+++ b/jedi/evaluate/helpers.py
@@ -19,7 +19,7 @@ def is_stdlib_path(path):
         return False
 
     base_path = os.path.join(sys.prefix, 'lib', 'python')
-    return bool(re.match(re.escape(base_path) + '\d.\d', path))
+    return bool(re.match(re.escape(base_path) + r'\d.\d', path))
 
 
 def deep_ast_copy(obj):
diff --git a/jedi/evaluate/utils.py b/jedi/evaluate/utils.py
index f6d7f870..990a995e 100644
--- a/jedi/evaluate/utils.py
+++ b/jedi/evaluate/utils.py
@@ -11,7 +11,7 @@ from jedi._compatibility import reraise
 _sep = os.path.sep
 if os.path.altsep is not None:
     _sep += os.path.altsep
-_path_re = re.compile('(?:\.[^{0}]+|[{0}]__init__\.py)$'.format(re.escape(_sep)))
+_path_re = re.compile(r'(?:\.[^{0}]+|[{0}]__init__\.py)$'.format(re.escape(_sep)))
 del _sep
 
 
diff --git a/jedi/utils.py b/jedi/utils.py
index 0f42e7d5..1338d1b3 100644
--- a/jedi/utils.py
+++ b/jedi/utils.py
@@ -138,5 +138,5 @@ def version_info():
     """
     Version = namedtuple('Version', 'major, minor, micro')
     from jedi import __version__
-    tupl = re.findall('[a-z]+|\d+', __version__)
+    tupl = re.findall(r'[a-z]+|\d+', __version__)
     return Version(*[x if i == 3 else int(x) for i, x in enumerate(tupl)])