diff --git a/avocado/utils/process.py b/avocado/utils/process.py
index d68431e969e2a0f31564d596ad328a34f438d2d3..6f38e22e09b70bdf300cd69635d3da614b0bf1f0 100644
--- a/avocado/utils/process.py
+++ b/avocado/utils/process.py
@@ -82,6 +82,10 @@ class CmdError(Exception):
         self.result = result
         self.additional_text = additional_text
 
+    def __str__(self):
+        return ("Command '%s' failed.\nstdout: %r\nstderr: %r\nadditional_info: %s" %
+                (self.command, self.result.stdout, self.result.stderr, self.additional_text))
+
 
 def can_sudo(cmd=None):
     """
diff --git a/selftests/unit/test_utils_process.py b/selftests/unit/test_utils_process.py
index 4577e04e807753e582efb200f61d9f7efe5823fd..7feb02d414833c543b9d68a870bda870a8070e90 100644
--- a/selftests/unit/test_utils_process.py
+++ b/selftests/unit/test_utils_process.py
@@ -15,7 +15,7 @@ from avocado.utils import gdb
 from avocado.utils import process
 from avocado.utils import path
 
-from six import string_types
+from six import string_types, PY2
 
 
 def probe_binary(binary):
@@ -306,6 +306,23 @@ class CmdResultTests(unittest.TestCase):
         self.assertRaises(TypeError, lambda x: result.stderr_text)
 
 
+class CmdErrorTests(unittest.TestCase):
+
+    def test_nasty_str(self):
+        result = process.CmdResult("ls", b"unicode_follows: \xc5\xa1",
+                                   b"cp1250 follows: \xfd", 1, 2, 3,
+                                   "wrong_encoding")
+        err = process.CmdError("ls", result, "please don't crash")
+        if PY2:
+            prefix = ''
+        else:
+            prefix = 'b'
+        self.assertEqual(str(err), "Command 'ls' failed.\nstdout: "
+                         "%s'unicode_follows: \\xc5\\xa1'\nstderr: "
+                         "%s'cp1250 follows: \\xfd'\nadditional_info: "
+                         "please don't crash" % (prefix, prefix))
+
+
 class FDDrainerTests(unittest.TestCase):
 
     def test_drain_from_pipe_fd(self):