diff --git a/HISTORY.md b/HISTORY.md
index 9ca135a..7f2c1dd 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -15,6 +15,7 @@ The following is the rough list of changes that went into different versions. I
 - Remove dependency on wait-connection-leonardo shell script. Fix issue #95
 - Add support for the Digilent chipKIT platform. (https://github.com/peplin)
 - Implement ard-parse-boards with shell scripting instead of Perl (https://github.com/peplin)
+- Compile with debugging symbols only when DEBUG=1 (https://github.com/peplin)
 
 ### 0.12.0 (2013-06-20)
 - Fix "generated_assembly" target, which got broken earlier. Fix issue #76 (https://github.com/matthijskooijman)
diff --git a/arduino-mk/Arduino.mk b/arduino-mk/Arduino.mk
index a494293..9a3fc06 100644
--- a/arduino-mk/Arduino.mk
+++ b/arduino-mk/Arduino.mk
@@ -764,8 +764,14 @@ endif
 # Using += instead of =, so that CPPFLAGS can be set per sketch level
 CPPFLAGS      += -$(MCU_FLAG_NAME)=$(MCU) -DF_CPU=$(F_CPU) -DARDUINO=$(ARDUINO_VERSION) \
         -I. -I$(ARDUINO_CORE_PATH) -I$(ARDUINO_VAR_PATH)/$(VARIANT) \
-        $(SYS_INCLUDES) $(USER_INCLUDES) -g -O$(OPTIMIZATION_LEVEL) -Wall \
-        -ffunction-sections -fdata-sections
+        $(SYS_INCLUDES) $(USER_INCLUDES) -Wall -ffunction-sections \
+        -fdata-sections
+
+ifdef DEBUG
+CPPFLAGS += -O0 -g
+else
+CPPFLAGS += -O$(OPTIMIZATION_LEVEL)
+endif
 
 # USB IDs for the Leonardo
 ifeq ($(VARIANT),leonardo)