diff --git a/include/libopencm3/stm32/f3/memorymap.h b/include/libopencm3/stm32/f3/memorymap.h
index 98aaee4e..f8b7909f 100644
--- a/include/libopencm3/stm32/f3/memorymap.h
+++ b/include/libopencm3/stm32/f3/memorymap.h
@@ -72,7 +72,7 @@
 #define TIM16_BASE			(PERIPH_BASE_APB2 + 0x4400)
 #define TIM15_BASE			(PERIPH_BASE_APB2 + 0x4000)
 /* PERIPH_BASE_APB2 + 0x3C00 (0x4001 3C00 - 0x4001 3FFF): Reserved */
-#define USART1_BASE			(PERIPH_BASE_APB2 + 0x1000)
+#define USART1_BASE			(PERIPH_BASE_APB2 + 0x3800)
 #define TIM8_BASE			(PERIPH_BASE_APB2 + 0x3400)
 #define SPI1_BASE			(PERIPH_BASE_APB2 + 0x3000)
 #define TIM1_BASE			(PERIPH_BASE_APB2 + 0x2C00)