diff --git a/arch/mips/src/pic32mx/Make.defs b/arch/mips/src/pic32mx/Make.defs
index aac5b19f17..6fbde1078e 100644
--- a/arch/mips/src/pic32mx/Make.defs
+++ b/arch/mips/src/pic32mx/Make.defs
@@ -66,7 +66,7 @@ endif
 CHIP_ASRCS  =
 CHIP_CSRCS  = pic32mx-irq.c pic32mx-decodeirq.c pic32mx-exception.c
 CHIP_CSRCS += pic32mx-gpio.c pic32mx-lowconsole.c pic32mx-lowinit.c
-CHIP_CSRCS += pic32mx-serial.c pic32mx-spi.cO
+CHIP_CSRCS += pic32mx-serial.c pic32mx-spi.c
 
 # Configuration-dependent PIC32MX files