diff --git a/S3/BaseUtils.py b/S3/BaseUtils.py
index 69590649..035be720 100644
--- a/S3/BaseUtils.py
+++ b/S3/BaseUtils.py
@@ -74,8 +74,8 @@
 
 
 
-RE_S3_DATESTRING = re.compile('\.[0-9]*(?:[Z\\-\\+]*?)')
-RE_XML_NAMESPACE = re.compile(b'^(<?[^>]+?>\s*|\s*)(<\w+) xmlns=[\'"](https?://[^\'"]+)[\'"]', re.MULTILINE)
+RE_S3_DATESTRING = re.compile('\\.[0-9]*(?:[Z\\-\\+]*?)')
+RE_XML_NAMESPACE = re.compile(b'^(<?[^>]+?>\\s*|\\s*)(<\\w+) xmlns=[\'"](https?://[^\'"]+)[\'"]', re.MULTILINE)
 
 
 # Date and time helpers
diff --git a/S3/Utils.py b/S3/Utils.py
index cf6e7482..88313b33 100644
--- a/S3/Utils.py
+++ b/S3/Utils.py
@@ -223,11 +223,11 @@ def time_to_epoch(t):
 
 def check_bucket_name(bucket, dns_strict=True):
     if dns_strict:
-        invalid = re.search("([^a-z0-9\.-])", bucket, re.UNICODE)
+        invalid = re.search(r"([^a-z0-9\.-])", bucket, re.UNICODE)
         if invalid:
             raise S3.Exceptions.ParameterError("Bucket name '%s' contains disallowed character '%s'. The only supported ones are: lowercase us-ascii letters (a-z), digits (0-9), dot (.) and hyphen (-)." % (bucket, invalid.groups()[0]))
     else:
-        invalid = re.search("([^A-Za-z0-9\._-])", bucket, re.UNICODE)
+        invalid = re.search(r"([^A-Za-z0-9\._-])", bucket, re.UNICODE)
         if invalid:
             raise S3.Exceptions.ParameterError("Bucket name '%s' contains disallowed character '%s'. The only supported ones are: us-ascii letters (a-z, A-Z), digits (0-9), dot (.), hyphen (-) and underscore (_)." % (bucket, invalid.groups()[0]))
 
@@ -238,13 +238,13 @@ def check_bucket_name(bucket, dns_strict=True):
     if dns_strict:
         if len(bucket) > 63:
             raise S3.Exceptions.ParameterError("Bucket name '%s' is too long (max 63 characters)" % bucket)
-        if re.search("-\.", bucket, re.UNICODE):
+        if re.search(r"-\.", bucket, re.UNICODE):
             raise S3.Exceptions.ParameterError("Bucket name '%s' must not contain sequence '-.' for DNS compatibility" % bucket)
-        if re.search("\.\.", bucket, re.UNICODE):
+        if re.search(r"\.\.", bucket, re.UNICODE):
             raise S3.Exceptions.ParameterError("Bucket name '%s' must not contain sequence '..' for DNS compatibility" % bucket)
-        if not re.search("^[0-9a-z]", bucket, re.UNICODE):
+        if not re.search(r"^[0-9a-z]", bucket, re.UNICODE):
             raise S3.Exceptions.ParameterError("Bucket name '%s' must start with a letter or a digit" % bucket)
-        if not re.search("[0-9a-z]$", bucket, re.UNICODE):
+        if not re.search(r"[0-9a-z]$", bucket, re.UNICODE):
             raise S3.Exceptions.ParameterError("Bucket name '%s' must end with a letter or a digit" % bucket)
     return True
 __all__.append("check_bucket_name")
diff --git a/run-tests.py b/run-tests.py
index 7ce84a11..a9f3f865 100755
--- a/run-tests.py
+++ b/run-tests.py
@@ -414,7 +414,7 @@ def pbucket(tail):
            must_find = ["ERROR: Upload of 'testsuite/permission-tests/permission-denied.txt' is not possible (Reason: Permission denied)",
                         "WARNING: 32 non-printable characters replaced in: crappy-file-name/non-printables",
            ],
-           must_not_find_re = ["demo/", "^(?!WARNING: Skipping).*\.png$", "permission-denied-dir"],
+           must_not_find_re = ["demo/", r"^(?!WARNING: Skipping).*\.png$", "permission-denied-dir"],
            retcode = EX_PARTIAL)
 
 ## ====== Create new file and sync with caching enabled
@@ -702,7 +702,7 @@ def pbucket(tail):
 ## ====== Verify ACL and MIME type
 test_s3cmd("Verify ACL and MIME type", ['info', '%s/copy/etc2/Logo.PNG' % pbucket(2) ],
     must_find_re = [ "MIME type:.*image/png",
-                     "ACL:.*\*anon\*: READ",
+                     r"ACL:.*\*anon\*: READ",
                      "URL:.*https?://%s.%s/copy/etc2/Logo.PNG" % (bucket(2), cfg.host_base) ],
            skip_if_profile = ['minio'])
 
@@ -716,7 +716,7 @@ def pbucket(tail):
 
 test_s3cmd("Verify ACL and MIME type", ['info', '%s/copy/etc2/Logo.PNG' % pbucket(2) ],
     must_find_re = [ "MIME type:.*binary/octet-stream",
-                     "ACL:.*\*anon\*: READ",
+                     r"ACL:.*\*anon\*: READ",
                      "URL:.*https?://%s.%s/copy/etc2/Logo.PNG" % (bucket(2), cfg.host_base) ],
            skip_if_profile = ['minio'])
 
@@ -731,7 +731,7 @@ def pbucket(tail):
 
 test_s3cmd("Verify ACL and MIME type", ['info', '%s/copy/etc2/Logo.PNG' % pbucket(2) ],
     must_find_re = [ "MIME type:.*image/png",
-                     "ACL:.*\*anon\*: READ",
+                     r"ACL:.*\*anon\*: READ",
                      "URL:.*https?://%s.%s/copy/etc2/Logo.PNG" % (bucket(2), cfg.host_base) ],
            skip_if_profile = ['minio'])