diff --git a/cores/arduino/HardwareSerial.cpp b/cores/arduino/HardwareSerial.cpp
index 561127f9f..4606db06b 100644
--- a/cores/arduino/HardwareSerial.cpp
+++ b/cores/arduino/HardwareSerial.cpp
@@ -177,6 +177,11 @@ int HardwareSerial::peek(void)
   }
 }
 
+int HardwareSerial::peekLast(void)
+{
+  return _rx_buffer_head==_rx_buffer_tail ? -1 : _rx_buffer[(SERIAL_RX_BUFFER_SIZE+_rx_buffer_tail-1)%SERIAL_RX_BUFFER_SIZE];
+}
+
 int HardwareSerial::read(void)
 {
   // if the head isn't ahead of the tail, we don't have any characters
diff --git a/cores/arduino/HardwareSerial.h b/cores/arduino/HardwareSerial.h
index 6ff29d0b9..ee946b1b1 100644
--- a/cores/arduino/HardwareSerial.h
+++ b/cores/arduino/HardwareSerial.h
@@ -123,6 +123,7 @@ class HardwareSerial : public Stream
     void end();
     virtual int available(void);
     virtual int peek(void);
+    virtual int peekLast(void);
     virtual int read(void);
     virtual int availableForWrite(void);
     virtual void flush(void);