Heavy quark correlations in hadronic collisions

We discuss results of the $k_t$ - factorization approach for heavy quark-heavy antiquark correlations in proton-proton and proton-antiproton collisions for RHIC, Tevatron and LHC. We consider correlations in the azimuthal angle as well as in the two-dimensional space of transverse momentum of heavy quark and heavy antiquark. We compare results obtained with the help of different unintegrated parton distributions (UPDF) from the literature.