diff --git a/glymur/jp2k.py b/glymur/jp2k.py
index 8d5272b..a42e291 100644
--- a/glymur/jp2k.py
+++ b/glymur/jp2k.py
@@ -233,6 +233,11 @@ class Jp2k(Jp2kBox):
                 msg = "Code block area cannot exceed 4096.  "
                 msg += "Code block height and width must be larger than 4."
                 raise RuntimeError(msg)
+            if ((math.log(h, 2) != math.floor(math.log(h, 2)) or
+                 math.log(w, 2) != math.floor(math.log(w, 2)))):
+                msg = "Bad code block size ({0}, {1}), "
+                msg += "must be powers of 2."
+                raise IOError(msg.format(h, w))
             cparams.cblockw_init = w
             cparams.cblockh_init = h
 
@@ -269,10 +274,16 @@ class Jp2k(Jp2kBox):
 
         if psizes is not None:
             for j, (prch, prcw) in enumerate(psizes):
+                if j == 0 and cbsize is not None:
+                    cblkh, cblkw = cbsize
+                    if cblkh * 2 > prch or cblkw * 2 > prcw:
+                        msg = "Highest Resolution precinct size must be at "
+                        msg += "least twice that of the code block dimensions."
+                        raise IOError(msg)
                 if ((math.log(prch, 2) != math.floor(math.log(prch, 2)) or
                      math.log(prcw, 2) != math.floor(math.log(prcw, 2)))):
-                    msg = "Bad precinct size ({0}, {1}), "
-                    msg += "must be multiple of 2."
+                    msg = "Bad precinct sizes ({0}, {1}), "
+                    msg += "must be powers of 2."
                     raise IOError(msg.format(prch, prcw))
 
                 cparams.prcw_init[j] = prcw
diff --git a/glymur/test/test_opj_suite_neg.py b/glymur/test/test_opj_suite_neg.py
index f33b981..0862c42 100644
--- a/glymur/test/test_opj_suite_neg.py
+++ b/glymur/test/test_opj_suite_neg.py
@@ -153,7 +153,7 @@ class TestSuiteNegative(unittest.TestCase):
             j = Jp2k(infile)
 
     def test_precinct_size_not_multiple_of_two(self):
-        # Seems like precinct size should be a multiple of two.
+        # Seems like precinct sizes should be powers of two.
         ifile = Jp2k(self.jp2file)
         data = ifile.read(reduce=3)
         with tempfile.NamedTemporaryFile(suffix='.jp2') as tfile:
@@ -161,5 +161,26 @@ class TestSuiteNegative(unittest.TestCase):
             with self.assertRaises(IOError) as ce:
                 ofile.write(data, psizes=[(13, 13)])
 
+    def test_codeblock_size_not_multiple_of_two(self):
+        # Seems like code block sizes should be powers of two.
+        ifile = Jp2k(self.jp2file)
+        data = ifile.read(reduce=3)
+        with tempfile.NamedTemporaryFile(suffix='.jp2') as tfile:
+            ofile = Jp2k(tfile.name, 'wb')
+            with self.assertRaises(IOError) as ce:
+                ofile.write(data, cbsize=(13, 12))
+
+    def test_codeblock_size_with_precinct_size(self):
+        # Seems like code block sizes should never exceed half that of 
+        # precinct size.
+        ifile = Jp2k(self.jp2file)
+        data = ifile.read(reduce=3)
+        with tempfile.NamedTemporaryFile(suffix='.jp2') as tfile:
+            ofile = Jp2k(tfile.name, 'wb')
+            with self.assertRaises(IOError) as ce:
+                ofile.write(data,
+                            cbsize=(64, 64),
+                            psizes=[(64, 64)])
+
 if __name__ == "__main__":
     unittest.main()