diff --git a/tests/unit/test_filters.py b/tests/unit/test_filters.py
index 69d26bf..6e729ad 100644
--- a/tests/unit/test_filters.py
+++ b/tests/unit/test_filters.py
@@ -220,6 +220,49 @@ def test_remove_all_json_post_data_parameters():
     assert request.body == b"{}"
 
 
+def test_replace_dict_post_data_parameters():
+    # This tests all of:
+    #   1. keeping a parameter
+    #   2. removing a parameter
+    #   3. replacing a parameter
+    #   4. replacing a parameter using a callable
+    #   5. removing a parameter using a callable
+    #   6. replacing a parameter that doesn't exist
+    body = {"one": "keep", "two": "lose", "three": "change", "four": "shout", "five": "whisper"}
+    request = Request("POST", "http://google.com", body, {})
+    request.headers["Content-Type"] = "application/x-www-form-urlencoded"
+    replace_post_data_parameters(
+        request,
+        [
+            ("two", None),
+            ("three", "tada"),
+            ("four", lambda key, value, request: value.upper()),
+            ("five", lambda key, value, request: None),
+            ("six", "doesntexist"),
+        ],
+    )
+    expected_data = {"one": "keep", "three": "tada", "four": "SHOUT"}
+    assert request.body == expected_data
+
+
+def test_remove_dict_post_data_parameters():
+    # Test the backward-compatible API wrapper.
+    body = {"id": "secret", "foo": "bar", "baz": "qux"}
+    request = Request("POST", "http://google.com", body, {})
+    request.headers["Content-Type"] = "application/x-www-form-urlencoded"
+    remove_post_data_parameters(request, ["id"])
+    expected_data = {"foo": "bar", "baz": "qux"}
+    assert request.body == expected_data
+
+
+def test_remove_all_dict_post_data_parameters():
+    body = {"id": "secret", "foo": "bar"}
+    request = Request("POST", "http://google.com", body, {})
+    request.headers["Content-Type"] = "application/x-www-form-urlencoded"
+    replace_post_data_parameters(request, [("id", None), ("foo", None)])
+    assert request.body == {}
+
+
 def test_decode_response_uncompressed():
     recorded_response = {
         "status": {"message": "OK", "code": 200},
diff --git a/vcr/filters.py b/vcr/filters.py
index 62254ed..8e00b64 100644
--- a/vcr/filters.py
+++ b/vcr/filters.py
@@ -84,7 +84,17 @@ def replace_post_data_parameters(request, replacements):
 
     replacements = dict(replacements)
     if request.method == "POST" and not isinstance(request.body, BytesIO):
-        if request.headers.get("Content-Type") == "application/json":
+        if isinstance(request.body, dict):
+            new_body = request.body.copy()
+            for k, rv in replacements.items():
+                if k in new_body:
+                    ov = new_body.pop(k)
+                    if callable(rv):
+                        rv = rv(key=k, value=ov, request=request)
+                    if rv is not None:
+                        new_body[k] = rv
+            request.body = new_body
+        elif request.headers.get("Content-Type") == "application/json":
             json_data = json.loads(request.body.decode("utf-8"))
             for k, rv in replacements.items():
                 if k in json_data: