diff --git a/README.md b/README.md
index ec38ba9..caa5c07 100644
--- a/README.md
+++ b/README.md
@@ -8,3 +8,11 @@ documentation](http://mjo.tc/atelier/2009/02/arduino-cli.html
 "Documentation") exists.
 
 If you're using Debian or Ubuntu, you can find this in the arduino-core package.
+
+## Options
+
+If you are defining your own `main()` function, you can stop the Ardunio's
+built-in `main()` from being compiled with your code by defining the
+`NO_CORE_MAIN_FUNCTION` variable:
+
+    NO_CORE_MAIN_FUNCTION = 1
diff --git a/arduino-mk/Arduino.mk b/arduino-mk/Arduino.mk
index 2d39095..4960d23 100644
--- a/arduino-mk/Arduino.mk
+++ b/arduino-mk/Arduino.mk
@@ -287,6 +287,11 @@ ifeq ($(strip $(NO_CORE)),)
 ifdef ARDUINO_CORE_PATH
 CORE_C_SRCS     = $(wildcard $(ARDUINO_CORE_PATH)/*.c)
 CORE_CPP_SRCS   = $(wildcard $(ARDUINO_CORE_PATH)/*.cpp)
+
+ifneq ($(strip $(NO_CORE_MAIN_FUNCTION)),)
+CORE_CPP_SRCS := $(filter-out %main.cpp, $(CORE_CPP_SRCS))
+endif
+
 CORE_OBJ_FILES  = $(CORE_C_SRCS:.c=.o) $(CORE_CPP_SRCS:.cpp=.o)
 CORE_OBJS       = $(patsubst $(ARDUINO_CORE_PATH)/%,  \
 			$(OBJDIR)/%,$(CORE_OBJ_FILES))