diff --git a/common.mk b/common.mk
index bef00a3c..09561cba 100644
--- a/common.mk
+++ b/common.mk
@@ -54,6 +54,11 @@ ifdef SLEEP_LED_ENABLE
     OPT_DEFS += -DNO_SUSPEND_POWER_DOWN
 endif
 
+ifdef BREATHING_LED_ENABLE
+    SRC += $(COMMON_DIR)/breathing_led.c
+    OPT_DEFS += -DBREATHING_LED_ENABLE
+endif
+
 ifdef BACKLIGHT_ENABLE
     SRC += $(COMMON_DIR)/backlight.c
     OPT_DEFS += -DBACKLIGHT_ENABLE
diff --git a/common/backlight.c b/common/backlight.c
index a0b2ce50..ee8169c6 100644
--- a/common/backlight.c
+++ b/common/backlight.c
@@ -16,6 +16,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #include "backlight.h"
+#include "breathing_led.h"
 #include "eeconfig.h"
 #include "debug.h"
 
@@ -33,7 +34,7 @@ void backlight_init(void)
 
 void backlight_increase(void)
 {
-#ifdef BACKLIGHT_CUSTOM
+#if defined(BACKLIGHT_CUSTOM) || defined(BREATHING_LED_ENABLE)
     if (backlight_config.enable) {
         if (backlight_config.level < BACKLIGHT_LEVELS) {
             backlight_config.level++;
@@ -42,6 +43,9 @@ void backlight_increase(void)
         dprintf("backlight custom increase: %u\n", backlight_config.level);
         backlight_set(backlight_config.level);
     }
+#ifdef BREATHING_LED_ENABLE
+    breathing_led_increase();
+#endif
 #else
     if(backlight_config.level < BACKLIGHT_LEVELS)
     {
@@ -56,7 +60,7 @@ void backlight_increase(void)
 
 void backlight_decrease(void)
 {
-#ifdef BACKLIGHT_CUSTOM
+#if defined(BACKLIGHT_CUSTOM) || defined(BREATHING_LED_ENABLE)
     if (backlight_config.enable) {
         if(backlight_config.level > 1)
         {
@@ -66,6 +70,9 @@ void backlight_decrease(void)
         dprintf("backlight custom decrease: %u\n", backlight_config.level);
         backlight_set(backlight_config.level);
     }
+#ifdef BREATHING_LED_ENABLE
+    breathing_led_decrease();
+#endif
 #else
     if(backlight_config.level > 0)
     {
@@ -80,16 +87,37 @@ void backlight_decrease(void)
 
 void backlight_toggle(void)
 {
+#ifdef BREATHING_LED_ENABLE
+    if (breathing_led_is_enabled()) {
+        breathing_led_disable();
+        backlight_disable();
+        return;
+    }
+#endif
     backlight_config.enable ^= 1;
-    if (backlight_config.enable)
-    {
+    if (backlight_config.enable) {
+#if defined(BACKLIGHT_CUSTOM) || defined(BREATHING_LED_ENABLE)
+        backlight_enable();
+#endif
         if (backlight_config.level == 0) {
             backlight_config.level = 1;
         }
     }
+    else {
+#ifndef BREATHING_LED_ENABLE
+#ifdef BACKLIGHT_CUSTOM
+        backlight_disable();
+#endif
+#endif
+    }
     eeconfig_write_backlight(backlight_config.raw);
     dprintf("backlight toggle: %u\n", backlight_config.enable);
     backlight_set(backlight_config.enable ? backlight_config.level : 0);
+#ifdef BREATHING_LED_ENABLE
+    if (!backlight_config.enable) {
+        breathing_led_enable();
+    }
+#endif
 }
 
 void backlight_step(void)
diff --git a/common/backlight.h b/common/backlight.h
index 685c422a..a33c727a 100644
--- a/common/backlight.h
+++ b/common/backlight.h
@@ -36,6 +36,9 @@ void backlight_decrease(void);
 void backlight_toggle(void);
 void backlight_step(void);
 
+void backlight_enable(void);
+void backlight_disable(void);
 void backlight_set(uint8_t level);
+void backlight_set_raw(uint8_t raw);
 
 #endif
diff --git a/common/breathing_led.c b/common/breathing_led.c
new file mode 100644
index 00000000..d71bf5b8
--- /dev/null
+++ b/common/breathing_led.c
@@ -0,0 +1,106 @@
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <avr/pgmspace.h>
+#include "led.h"
+#include "breathing_led.h"
+#include "backlight.h"
+#include "debug.h"
+
+#define BREATHING_LED_TIMER_TOP F_CPU/64
+
+breathing_led_config_t breathing_led_config;
+
+void breathing_led_init(void)
+{
+    /* Timer3 setup */
+    /* CTC mode */
+    TCCR3B |= _BV(WGM12);
+    /* Clock selelct: clk/1 */
+    TCCR3B |= _BV(CS10);
+    /* Set TOP value */
+    uint8_t sreg = SREG;
+    cli();
+    OCR3AH = (BREATHING_LED_TIMER_TOP>>8)&0xff;
+    OCR3AL = BREATHING_LED_TIMER_TOP&0xff;
+    SREG = sreg;
+}
+
+bool breathing_led_is_enabled(void)
+{
+    return breathing_led_config.enable;
+}
+
+void breathing_led_enable(void)
+{
+    /* Enable Compare Match Interrupt */
+    TIMSK3 |= _BV(OCIE3A);
+    breathing_led_config.enable = true;
+    dprintf("breathing led on: %u\n", breathing_led_config.enable);
+    eeconfig_write_breathing_led(breathing_led_config.raw);
+}
+
+void breathing_led_disable(void)
+{
+    /* Disable Compare Match Interrupt */
+    TIMSK3 &= ~_BV(OCIE3A);
+    breathing_led_config.enable = false;
+    dprintf("breathing led off: %u\n", breathing_led_config.enable);
+    eeconfig_write_breathing_led(breathing_led_config.raw);
+}
+
+void breathing_led_toggle(void)
+{
+    /* Disable Compare Match Interrupt */
+    TIMSK3 ^= _BV(OCIE3A);
+    breathing_led_config.enable ^= 1;
+    dprintf("breathing led toggle: %u\n", breathing_led_config.enable);
+    eeconfig_write_breathing_led(breathing_led_config.raw);
+}
+
+void breathing_led_increase(void)
+{
+    if (breathing_led_config.enable) {
+        if (breathing_led_config.level < BREATHING_LED_LEVELS) {
+            breathing_led_config.level++;
+            eeconfig_write_breathing_led(breathing_led_config.raw);
+        }
+        dprintf("breathing led speed increase: %u\n", breathing_led_config.level);
+    }
+}
+
+void breathing_led_decrease(void)
+{
+    if (breathing_led_config.enable) {
+        if (breathing_led_config.level > 0)
+        {
+            breathing_led_config.level--;
+            eeconfig_write_breathing_led(breathing_led_config.raw);
+        }
+        dprintf("breathing led speed decrease: %u\n", breathing_led_config.level);
+    }
+}
+
+/* Breathing LED brighness(PWM On period) table
+ * (64[steps] * 4[duration]) / 64[PWM periods/s] = 4 second breath cycle
+ *
+ * http://www.wolframalpha.com/input/?i=%28sin%28+x%2F64*pi%29**8+*+255%2C+x%3D0+to+63
+ * (0..63).each {|x| p ((sin(x/64.0*PI)**8)*255).to_i }
+ */
+static const uint8_t breathing_table[64] PROGMEM = {
+0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 4, 6, 10,
+15, 23, 32, 44, 58, 74, 93, 113, 135, 157, 179, 199, 218, 233, 245, 252,
+255, 252, 245, 233, 218, 199, 179, 157, 135, 113, 93, 74, 58, 44, 32, 23,
+15, 10, 6, 4, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+};
+
+ISR(TIMER3_COMPA_vect)
+{
+    uint8_t index = 0;
+    uint8_t step = 0;
+    step++;
+    if (step >= BREATHING_LED_LEVELS - breathing_led_config.level) {
+        step = 0;
+        index++;
+        backlight_set_raw(pgm_read_byte(&breathing_table[index]));
+    }
+}
diff --git a/common/breathing_led.h b/common/breathing_led.h
new file mode 100644
index 00000000..fb31668f
--- /dev/null
+++ b/common/breathing_led.h
@@ -0,0 +1,39 @@
+#ifndef BREATHING_LED_H
+#define BREATHING_LED_H
+
+
+#ifdef BREATHING_LED_ENABLE
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifndef BREATHING_LED_LEVEL
+#define BREATHING_LED_LEVEL 1
+#endif
+
+typedef union {
+    uint8_t raw;
+    struct {
+        bool    enable:1;
+        uint8_t level:7;
+    };
+} breathing_led_config_t;
+
+void breathing_led_init(void);
+bool breathing_led_is_enabled(void);
+void breathing_led_enable(void);
+void breathing_led_disable(void);
+void breathing_led_toggle(void);
+void breathing_led_increase(void);
+void breathing_led_decrease(void);
+
+#else
+
+#define breathing_led_init()
+#define breathing_led_enable()
+#define breathing_led_disable()
+#define breathing_led_toggle()
+
+#endif
+
+#endif
diff --git a/common/eeconfig.c b/common/eeconfig.c
index 5aadf1c5..ab9bae3c 100644
--- a/common/eeconfig.c
+++ b/common/eeconfig.c
@@ -14,6 +14,9 @@ void eeconfig_init(void)
 #ifdef BACKLIGHT_ENABLE
     eeprom_write_byte(EECONFIG_BACKLIGHT,      0);
 #endif
+#ifdef BREATHING_LED_ENABLE
+    eeprom_write_byte(EECONFIG_BREATHING_LED,  0);
+#endif
 #ifdef KEYMAP_EX_ENABLE
     keymap_ex_init();
 #endif
@@ -50,3 +53,8 @@ void eeconfig_write_keymap(uint8_t val) { eeprom_write_byte(EECONFIG_KEYMAP, val
 uint8_t eeconfig_read_backlight(void)      { return eeprom_read_byte(EECONFIG_BACKLIGHT); }
 void eeconfig_write_backlight(uint8_t val) { eeprom_write_byte(EECONFIG_BACKLIGHT, val); }
 #endif
+
+#ifdef BREATHING_LED_ENABLE
+uint8_t eeconfig_read_breathing_led(void)      { return eeprom_read_byte(EECONFIG_BREATHING_LED); }
+void eeconfig_write_breathing_led(uint8_t val) { eeprom_write_byte(EECONFIG_BREATHING_LED, val); }
+#endif
diff --git a/common/eeconfig.h b/common/eeconfig.h
index e1b5ae28..36c18143 100644
--- a/common/eeconfig.h
+++ b/common/eeconfig.h
@@ -31,6 +31,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define EECONFIG_KEYMAP                             (uint8_t *)4
 #define EECONFIG_MOUSEKEY_ACCEL                     (uint8_t *)5
 #define EECONFIG_BACKLIGHT                          (uint8_t *)6
+#define EECONFIG_BREATHING_LED                      (uint8_t *)7
 
 
 /* debug bit */
@@ -71,4 +72,9 @@ uint8_t eeconfig_read_backlight(void);
 void eeconfig_write_backlight(uint8_t val);
 #endif
 
+#ifdef BREATHING_LED_ENABLE
+uint8_t eeconfig_read_breathing_led(void);
+void eeconfig_write_breathing_led(uint8_t val);
+#endif
+
 #endif