diff --git a/.travis.yml b/.travis.yml
index 032054674..acdee4e81 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -60,6 +60,16 @@ jobs:
     - make flake
   - <<: *FLAKE
     python: "3.7"
+  - &MYPY
+    name: mypy
+    cache: false
+    python: "3.6"
+    install:
+    - pip install -r tests/requirements.txt
+    script:
+    - make mypy
+  - <<: *MYPY
+    python: "3.7"
   # Run examples Python 3.6, 3.7 and system Redis
   - &EXAMPLES
     stage: examples
diff --git a/CONTRIBUTORS.txt b/CONTRIBUTORS.txt
index d3a89d09d..dd1efbbc0 100644
--- a/CONTRIBUTORS.txt
+++ b/CONTRIBUTORS.txt
@@ -27,6 +27,7 @@ Marijn Giesen
 Martin <the-panda>
 Michael Käufl
 Nickolai Novik
+Oleg Butuzov
 Pau Freixes
 Paul Colomiets
 Samuel Colvin
diff --git a/Makefile b/Makefile
index 22b9d310f..9a7740d38 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,7 @@
 PYTHON ?= python3
 FLAKE ?= flake8
 PYTEST ?= pytest
+MYPY ?= mypy
 
 REDIS_VERSION ?= "$(shell redis-cli INFO SERVER | sed -n 2p)"
 REDIS_TAGS ?= 2.6.17 2.8.22 3.0.7 3.2.8 4.0.11 5.0.1
@@ -34,6 +35,9 @@ flake:
 	@echo "Job is not configured to run on $(PYTHON_IMPL); skipped."
 endif
 
+mypy:
+	$(MYPY) aioredis --ignore-missing-imports
+
 test:
 	$(PYTEST)
 
diff --git a/aioredis/errors.py b/aioredis/errors.py
index b73e2e424..3a41a25d4 100644
--- a/aioredis/errors.py
+++ b/aioredis/errors.py
@@ -1,3 +1,5 @@
+from typing import Optional, Sequence
+
 __all__ = [
     'RedisError',
     'ProtocolError',
@@ -28,7 +30,7 @@ class ProtocolError(RedisError):
 class ReplyError(RedisError):
     """Raised for redis error replies (-ERR)."""
 
-    MATCH_REPLY = None
+    MATCH_REPLY = None  # type: Optional[Sequence[str]]
 
     def __new__(cls, msg, *args):
         for klass in cls.__subclasses__():
@@ -37,6 +39,7 @@ def __new__(cls, msg, *args):
         return super().__new__(cls, msg, *args)
 
 
+
 class MaxClientsError(ReplyError):
     """Raised for redis server when the maximum number of client has been
     reached."""
diff --git a/aioredis/parser.py b/aioredis/parser.py
index 99699e5fd..c3f05d9ce 100644
--- a/aioredis/parser.py
+++ b/aioredis/parser.py
@@ -1,23 +1,24 @@
 from .errors import ProtocolError, ReplyError
+from typing import Optional, Generator, Callable, Iterator
 
 __all__ = [
     'Reader', 'PyReader',
 ]
 
-
 class PyReader:
     """Pure-Python Redis protocol parser that follows hiredis.Reader
     interface (except setmaxbuf/getmaxbuf).
     """
-    def __init__(self, protocolError=ProtocolError, replyError=ReplyError,
-                 encoding=None):
+    def __init__(self, protocolError: Callable = ProtocolError,
+                 replyError: Callable = ReplyError,
+                 encoding: Optional[str] = None):
         if not callable(protocolError):
             raise TypeError("Expected a callable")
         if not callable(replyError):
             raise TypeError("Expected a callable")
         self._parser = Parser(protocolError, replyError, encoding)
 
-    def feed(self, data, o=0, l=-1):
+    def feed(self, data, o: int = 0, l: int = -1):
         """Feed data to parser."""
         if l == -1:
             l = len(data) - o
@@ -35,31 +36,33 @@ def gets(self):
         """
         return self._parser.parse_one()
 
-    def setmaxbuf(self, size):
+    def setmaxbuf(self, size: Optional[int] ) -> None:
         """No-op."""
         pass
 
-    def getmaxbuf(self):
+    def getmaxbuf(self) -> int:
         """No-op."""
         return 0
 
 
 class Parser:
-    def __init__(self, protocolError, replyError, encoding):
-        self.buf = bytearray()
-        self.pos = 0
-        self.protocolError = protocolError
-        self.replyError = replyError
-        self.encoding = encoding
+    def __init__(self, protocolError: Callable,
+                 replyError: Callable, encoding: Optional[str] ):
+
+        self.buf = bytearray()  # type: bytearray
+        self.pos = 0  # type: int
+        self.protocolError = protocolError  # type: Callable
+        self.replyError = replyError  # type: Callable
+        self.encoding = encoding  # type: Optional[str]
         self._err = None
-        self._gen = None
+        self._gen = None # type: Optional[Generator]
 
-    def waitsome(self, size):
+    def waitsome(self, size: int) -> Iterator[bool]:
         # keep yielding false until at least `size` bytes added to buf.
         while len(self.buf) < self.pos+size:
             yield False
 
-    def waitany(self):
+    def waitany(self) -> Iterator[bool]:
         yield from self.waitsome(len(self.buf) + 1)
 
     def readone(self):
@@ -69,7 +72,7 @@ def readone(self):
         self.pos += 1
         return val
 
-    def readline(self, size=None):
+    def readline(self, size: Optional[int] = None):
         if size is not None:
             if len(self.buf) < size + 2 + self.pos:
                 yield from self.waitsome(size + 2)
@@ -96,7 +99,7 @@ def error(self, msg):
         self._err = self.protocolError(msg)
         return self._err
 
-    def parse(self, is_bulk=False):
+    def parse(self, is_bulk: bool = False):
         if self._err is not None:
             raise self._err
         ctl = yield from self.readone()
@@ -156,7 +159,6 @@ def parse_one(self):
         else:
             return False
 
-
 try:
     import hiredis
     Reader = hiredis.Reader
diff --git a/tests/requirements.txt b/tests/requirements.txt
index a88d2f006..7b820b33d 100644
--- a/tests/requirements.txt
+++ b/tests/requirements.txt
@@ -5,3 +5,4 @@ pytest==4.1.1
 pytest-cov==2.6.1
 pytest-xdist==1.26.0
 async-timeout==3.0.1
+mypy