diff --git a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/json/JSONUtil.java b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/json/JSONUtil.java
index 346f319e6..301574ea7 100644
--- a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/json/JSONUtil.java
+++ b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/json/JSONUtil.java
@@ -28,6 +28,7 @@ import java.util.Map.Entry;
 
 import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
+import com.google.gson.JsonNull;
 import com.google.gson.JsonObject;
 
 public class JSONUtil {
@@ -73,7 +74,7 @@ public class JSONUtil {
 
   public static String str(JsonObject json, String name) {
     JsonElement e = json.get(name);
-    return e == null ? null : e.getAsString();
+    return e == null || e instanceof JsonNull ? null : e.getAsString();
   }
 
   public static String str(JsonObject json, String name1, String name2) {