diff --git a/compose/config/config.py b/compose/config/config.py
index 1e793d9f6..6cffa2fe8 100644
--- a/compose/config/config.py
+++ b/compose/config/config.py
@@ -4,7 +4,7 @@ import sys
 import yaml
 from collections import namedtuple
 import json
-import jsonschema
+from jsonschema import Draft4Validator, FormatChecker, ValidationError
 
 import six
 
@@ -133,6 +133,28 @@ def get_config_path(base_dir):
     return os.path.join(path, winner)
 
 
+@FormatChecker.cls_checks(format="ports", raises=ValidationError("Ports is incorrectly formatted."))
+def format_ports(instance):
+    def _is_valid(port):
+        if ':' in port or '/' in port:
+            return True
+        try:
+            int(port)
+            return True
+        except ValueError:
+            return False
+        return False
+
+    if isinstance(instance, list):
+        for port in instance:
+            if not _is_valid(port):
+                return False
+        return True
+    elif isinstance(instance, str):
+        return _is_valid(instance)
+    return False
+
+
 def validate_against_schema(config):
     config_source_dir = os.path.dirname(os.path.abspath(__file__))
     schema_file = os.path.join(config_source_dir, "schema.json")
@@ -140,7 +162,7 @@ def validate_against_schema(config):
     with open(schema_file, "r") as schema_fh:
         schema = json.load(schema_fh)
 
-    validation_output = jsonschema.Draft4Validator(schema)
+    validation_output = Draft4Validator(schema, format_checker=FormatChecker(["ports"]))
 
     errors = [error.message for error in sorted(validation_output.iter_errors(config), key=str)]
     if errors:
diff --git a/compose/schema.json b/compose/schema.json
index 7c7e2d096..bf43ca36b 100644
--- a/compose/schema.json
+++ b/compose/schema.json
@@ -14,6 +14,17 @@
       "type": "object",
 
       "properties": {
+        "ports": {
+          "oneOf": [
+            {"type": "string", "format": "ports"},
+            {
+              "type": "array",
+              "items": {"type": "string"},
+              "uniqueItems": true,
+              "format": "ports"
+            }
+          ]
+        },
         "build": {"type": "string"},
         "env_file": {"$ref": "#/definitions/string_or_list"},
         "environment": {
diff --git a/tests/unit/config_test.py b/tests/unit/config_test.py
index f06cbab63..f7e949d3c 100644
--- a/tests/unit/config_test.py
+++ b/tests/unit/config_test.py
@@ -80,6 +80,28 @@ class ConfigTest(unittest.TestCase):
                 )
             )
 
+    def test_config_invalid_ports_format_validation(self):
+        with self.assertRaises(config.ConfigurationError):
+            for invalid_ports in [{"1": "8000"}, "whatport"]:
+                config.load(
+                    config.ConfigDetails(
+                        {'web': {'image': 'busybox', 'ports': invalid_ports}},
+                        'working_dir',
+                        'filename.yml'
+                    )
+                )
+
+    def test_config_valid_ports_format_validation(self):
+        valid_ports = [["8000", "9000"], "625", "8000:8050", ["8000/8050"]]
+        for ports in valid_ports:
+            config.load(
+                config.ConfigDetails(
+                    {'web': {'image': 'busybox', 'ports': ports}},
+                    'working_dir',
+                    'filename.yml'
+                )
+            )
+
 
 class InterpolationTest(unittest.TestCase):
     @mock.patch.dict(os.environ)