diff --git a/Makefile.Pi.Adafruit b/Makefile.Pi.Adafruit
index 9cf8ab7..3ba9993 100644
--- a/Makefile.Pi.Adafruit
+++ b/Makefile.Pi.Adafruit
@@ -3,7 +3,7 @@
 CC      = gcc
 CXX     = g++
 CFLAGS  = -g -O3 -Wall -std=c++0x -DHD44780 -DADAFRUIT_DISPLAY -I/usr/local/include
-LIBS    = -lwiringPi -lwiringPiDev
+LIBS    = -lwiringPi -lwiringPiDev -lpthread
 LDFLAGS = -g -L/usr/local/lib
 
 OBJECTS = \
diff --git a/Makefile.Pi.HD44780 b/Makefile.Pi.HD44780
index 0a93437..1b7ef22 100644
--- a/Makefile.Pi.HD44780
+++ b/Makefile.Pi.HD44780
@@ -3,7 +3,7 @@
 CC      = gcc
 CXX     = g++
 CFLAGS  = -g -O3 -Wall -std=c++0x -DHD44780 -I/usr/local/include
-LIBS    = -lwiringPi -lwiringPiDev
+LIBS    = -lwiringPi -lwiringPiDev -lpthread
 LDFLAGS = -g -L/usr/local/lib
 
 OBJECTS = \