diff --git a/src/openeo_pg_parser/translate.py b/src/openeo_pg_parser/translate.py
index add5ca9..dd4418a 100644
--- a/src/openeo_pg_parser/translate.py
+++ b/src/openeo_pg_parser/translate.py
@@ -286,7 +286,7 @@ def translate_process_graph(pg_filepath, process_defs=None, parameters=None):
 
     # remove first layer of the process graph
     parameters = {} if parameters is None else parameters
-    if "parameters" in process_graph.keys():
+    if process_graph.get("parameters"):
         for parameter_def in process_graph['parameters']:
             parameter = OpenEOParameter(parameter_def)
             parameters.update({parameter.name: parameter.default_value})
diff --git a/tests/process_graphs/none.json b/tests/process_graphs/none.json
new file mode 100644
index 0000000..c7077d0
--- /dev/null
+++ b/tests/process_graphs/none.json
@@ -0,0 +1,23 @@
+{
+  "id": "none-pg",
+  "summary": null,
+  "description": null,
+  "returns": null,
+  "parameters": null,
+  "process_graph": {
+    "sub": {
+      "process_id": "subtract",
+      "arguments": {
+        "data": [
+          {
+            "from_argument": "nir"
+          },
+          {
+            "from_argument": "red"
+          }
+        ]
+      },
+      "result": true
+    }
+  }
+}
diff --git a/tests/test_translate.py b/tests/test_translate.py
index bdbab8d..b3ddbff 100644
--- a/tests/test_translate.py
+++ b/tests/test_translate.py
@@ -17,6 +17,13 @@ def test_translate_process_graph(self):
         print(graph)
         assert True
 
+    def test_translate_process_graph_none_params(self):
+        """Translate a minimal process graph with all allowed values set to None."""
+        pg_file = os.path.join(self.pg_dirpath, "none.json")
+        graph = translate_process_graph(pg_file)
+        print(graph)
+        assert True
+
     def test_process_graph_not_found(self):
         """ Checks if an error is thrown when a process graph file cannot be found. """
         pg_filepath = os.path.join(self.pg_dirpath, "does_not_exist.json")