diff --git a/cores/arduino/Print.cpp b/cores/arduino/Print.cpp
index e541a6c..98969f5 100755
--- a/cores/arduino/Print.cpp
+++ b/cores/arduino/Print.cpp
@@ -226,6 +226,8 @@ size_t Print::printFloat(double number, uint8_t digits)
 { 
   size_t n = 0;
   
+  if (isnan(number)) return print("nan");
+  
   // Handle negative numbers
   if (number < 0.0)
   {