diff --git a/src/main/scala/cc/spray/json/BasicFormats.scala b/src/main/scala/cc/spray/json/BasicFormats.scala
index e16b4caf..32ae91e8 100644
--- a/src/main/scala/cc/spray/json/BasicFormats.scala
+++ b/src/main/scala/cc/spray/json/BasicFormats.scala
@@ -42,6 +42,7 @@ trait BasicFormats {
     def write(x: Float) = JsNumber(x)
     def read(value: JsValue) = value match {
       case JsNumber(x) => x.floatValue
+      case JsNull      => Float.NaN
       case _ => throw new DeserializationException("Float expected")
     }
   }
@@ -50,6 +51,7 @@ trait BasicFormats {
     def write(x: Double) = JsNumber(x)
     def read(value: JsValue) = value match {
       case JsNumber(x) => x.doubleValue
+      case JsNull      => Double.NaN
       case _ => throw new DeserializationException("Double expected")
     }
   }
@@ -124,4 +126,4 @@ trait BasicFormats {
     }
   }
   
-}
\ No newline at end of file
+}
diff --git a/src/test/scala/cc/spray/json/BasicFormatsSpec.scala b/src/test/scala/cc/spray/json/BasicFormatsSpec.scala
index 7f74e379..11576a44 100644
--- a/src/test/scala/cc/spray/json/BasicFormatsSpec.scala
+++ b/src/test/scala/cc/spray/json/BasicFormatsSpec.scala
@@ -38,6 +38,9 @@ class BasicFormatsSpec extends Specification with DefaultJsonProtocol {
     "convert a JsNumber to a Float" in {
       JsNumber(4.2f).fromJson[Float] mustEqual 4.2f 
     }
+    "convert a JsNull to a Float" in {
+      JsNull.fromJson[Float].isNaN mustEqual Float.NaN.isNaN
+    }
   }
   
   "The DoubleJsonFormat" should {
@@ -56,6 +59,9 @@ class BasicFormatsSpec extends Specification with DefaultJsonProtocol {
     "convert a JsNumber to a Double" in {
       JsNumber(4.2).fromJson[Double] mustEqual 4.2 
     }
+    "convert a JsNull to a Double" in {
+      JsNull.fromJson[Double].isNaN mustEqual Double.NaN.isNaN
+    }
   }
   
   "The ByteJsonFormat" should {