diff --git a/libmodbus.pc.in b/libmodbus.pc.in
index 0c869df..f1a9cbf 100644
--- a/libmodbus.pc.in
+++ b/libmodbus.pc.in
@@ -7,4 +7,4 @@ Name: modbus
 Description: Modbus library
 Version: @VERSION@
 Libs: -L${libdir} -lmodbus
-Cflags: -I${includedir}
+Cflags: -I${includedir}/modbus