One of the multiple factors required for polyadenylation and 3'-end cleavage of mammalian pre-mRNAs. Homodimer. The CSTF complex is composed of CSTF1 (50 kDa subunit), CSTF2 (64 kDa subunit) and CSTF3 (77 kDa subunit). CSTF3 directly interacts with CSTF1 and CSTF2. Interacts with FIP1L1 (By similarity).