diff --git a/src/common_io.h b/src/common_io.h
index fe69dd0b753c8bdced38c97e155247f117b01590..5e02d670cc323899f7bacdc1ffc3539cbcacba65 100644
--- a/src/common_io.h
+++ b/src/common_io.h
@@ -32,7 +32,6 @@
 #define IO_BUFFER_ALIGNMENT 1024
 
 /* Avoid cyclic inclusion problems */
-struct cosmology;
 struct part;
 struct gpart;
 struct spart;