diff --git a/mitogen/core.py b/mitogen/core.py
index e5a714f3..e369a48a 100644
--- a/mitogen/core.py
+++ b/mitogen/core.py
@@ -26,8 +26,6 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
-import cPickle
-import cStringIO
 import collections
 import errno
 import fcntl
@@ -40,7 +38,6 @@ import signal
 import socket
 import struct
 import sys
-import thread
 import threading
 import time
 import traceback
@@ -48,6 +45,16 @@ import warnings
 import weakref
 import zlib
 
+try:
+    import cPickle
+except ImportError:
+    import pickle as cPickle
+
+try:
+    from cStringIO import StringIO as BytesIO
+except ImportError:
+    from io import BytesIO
+
 # TODO: usage of 'import' after setting __name__, but before fixing up
 # sys.modules generates a warning. This happens when profiling = True.
 warnings.filterwarnings('ignore',
@@ -69,6 +76,12 @@ ALLOCATE_ID = 105
 SHUTDOWN = 106
 LOAD_MODULE = 107
 
+PY3 = sys.version_info > (3,)
+if PY3:
+    b = lambda s: s.encode('latin-1')
+else:
+    b = str
+
 CHUNK_SIZE = 131072
 _tls = threading.local()
 
@@ -344,9 +357,12 @@ class Message(object):
         _vv and IOLOG.debug('%r.unpickle()', self)
         obj = self._unpickled
         if obj is Message._unpickled:
-            fp = cStringIO.StringIO(self.data)
+            fp = BytesIO(self.data)
             unpickler = cPickle.Unpickler(fp)
-            unpickler.find_global = self._find_global
+            try:
+                unpickler.find_global = self._find_global
+            except AttributeError:
+                unpickler.find_class = self._find_global
 
             try:
                 # Must occur off the broker thread.
@@ -679,7 +695,10 @@ class Importer(object):
             flags = 0x4000
         source = self.get_source(fullname)
         code = compile(source, mod.__file__, 'exec', flags, True)
-        exec code in vars(mod)
+        if PY3:
+            exec(code, vars(mod))
+        else:
+            exec('exec code in vars(mod)')
         return mod
 
     def get_filename(self, fullname):
@@ -1154,7 +1173,7 @@ class Waker(BasicStream):
                 self._broker.shutdown()
 
     def defer(self, func, *args, **kwargs):
-        if thread.get_ident() == self.broker_ident:
+        if threading.currentThread().ident == self.broker_ident:
             _vv and IOLOG.debug('%r.defer() [immediate]', self)
             return func(*args, **kwargs)
 
@@ -1169,7 +1188,7 @@ class Waker(BasicStream):
         # of tearing itself down, the waker fd may already have been closed, so
         # ignore EBADF here.
         try:
-            self.transmit_side.write(' ')
+            self.transmit_side.write(b(' '))
         except OSError:
             e = sys.exc_info()[1]
             if e[0] != errno.EBADF:
diff --git a/mitogen/parent.py b/mitogen/parent.py
index f1974907..c100c4fd 100644
--- a/mitogen/parent.py
+++ b/mitogen/parent.py
@@ -26,7 +26,6 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
-import cStringIO
 import fcntl
 import getpass
 import inspect
@@ -43,6 +42,11 @@ import time
 import types
 import zlib
 
+try:
+    from cStringIO import StringIO as BytesIO
+except ImportError:
+    from io import BytesIO
+
 if sys.version_info < (2, 7, 11):
     from mitogen.compat import tokenize
 else:
@@ -97,7 +101,7 @@ def is_immediate_child(msg, stream):
 def minimize_source(source):
     """Remove most comments and docstrings from Python source code.
     """
-    tokens = tokenize.generate_tokens(cStringIO.StringIO(source).readline)
+    tokens = tokenize.generate_tokens(BytesIO(source).readline)
     tokens = strip_comments(tokens)
     tokens = strip_docstrings(tokens)
     tokens = reindent(tokens)
diff --git a/mitogen/ssh.py b/mitogen/ssh.py
index 15e9ac02..0507bb51 100644
--- a/mitogen/ssh.py
+++ b/mitogen/ssh.py
@@ -30,10 +30,14 @@
 Functionality to allow establishing new slave contexts over an SSH connection.
 """
 
-import commands
 import logging
 import time
 
+try:
+    from shlex import quote as shlex_quote
+except ImportError:
+    from pipes import quote as shlex_quote
+
 import mitogen.parent
 
 
@@ -108,7 +112,7 @@ class Stream(mitogen.parent.Stream):
             bits += self.ssh_args
         bits.append(self.hostname)
         base = super(Stream, self).get_boot_command()
-        return bits + [commands.mkarg(s).strip() for s in base]
+        return bits + [shlex_quote(s).strip() for s in base]
 
     def connect(self):
         super(Stream, self).connect()