diff --git a/arch/arm/src/stm32/stm32_serial.c b/arch/arm/src/stm32/stm32_serial.c
index 6425cd2d91..77c07ea68e 100644
--- a/arch/arm/src/stm32/stm32_serial.c
+++ b/arch/arm/src/stm32/stm32_serial.c
@@ -189,7 +189,7 @@
 #  define RXDMA_MUTIPLE_MASK  (RXDMA_MUTIPLE -1)
 #  define RXDMA_BUFFER_SIZE   ((CONFIG_STM32_SERIAL_RXDMA_BUFFER_SIZE \
                                 + RXDMA_MUTIPLE_MASK) \
-                                & ~RXDMA_MUTIPLE_MASK))
+                                & ~RXDMA_MUTIPLE_MASK)
 
 /* DMA priority */