diff --git a/main/src/com/google/refine/expr/functions/Coalesce.java b/main/src/com/google/refine/expr/functions/Coalesce.java
index ffdcc9b1c..5ef489c35 100644
--- a/main/src/com/google/refine/expr/functions/Coalesce.java
+++ b/main/src/com/google/refine/expr/functions/Coalesce.java
@@ -46,7 +46,7 @@ public class Coalesce implements Function {
 
     @Override
     public Object call(Properties bindings, Object[] args) {
-        if (args.length> 0) {
+        if (args.length> 1) {
             for (int i = 0; i < args.length; i++){
                 if (args[i] == null) {
                     continue;
@@ -56,7 +56,7 @@ public class Coalesce implements Function {
             }
             return null;
         }
-        return new EvalError(ControlFunctionRegistry.getFunctionName(this) + " expects at least one argument");
+        return new EvalError(ControlFunctionRegistry.getFunctionName(this) + " expects at least two arguments");
     }
 
     @Override
@@ -65,8 +65,8 @@ public class Coalesce implements Function {
     
         writer.object();
         writer.key("description"); writer.value("Returns the first non-null from a series of values");
-        writer.key("params"); writer.value("one or more objects");
-        writer.key("returns"); writer.value("object");
+        writer.key("params"); writer.value("two or more objects");
+        writer.key("returns"); writer.value("object or null");
         writer.endObject();
     }
 }
diff --git a/main/tests/server/src/com/google/refine/tests/expr/functions/CoalesceTests.java b/main/tests/server/src/com/google/refine/tests/expr/functions/CoalesceTests.java
index 3e1072bcf..a2f1be5fa 100644
--- a/main/tests/server/src/com/google/refine/tests/expr/functions/CoalesceTests.java
+++ b/main/tests/server/src/com/google/refine/tests/expr/functions/CoalesceTests.java
@@ -88,13 +88,12 @@ public class CoalesceTests extends RefineTest {
     @Test
     public void testCoalesceInvalidParams() {        
         Assert.assertTrue(invoke("coalesce") instanceof EvalError);
+        Assert.assertTrue(invoke("coalesce", 1) instanceof EvalError);
     }
     
     @Test
-    public void testCoalesce() {        
-        Assert.assertNull(invoke("coalesce", (Object) null));
-        Assert.assertEquals(invoke("coalesce", "string"),"string");
-        Assert.assertEquals(invoke("coalesce", 1),1);
+    public void testCoalesce() {
+        Assert.assertNull(invoke("coalesce", (Object) null, (Object) null));
         Assert.assertEquals(invoke("coalesce", (Object) null, "string"),"string");
         Assert.assertEquals(invoke("coalesce", (Object) null, (Object) null, "string"),"string");
         Assert.assertEquals(invoke("coalesce", (Object) null, 1),1);