The astroparticle physics working group witnessed intense discussion and activity covering a broad range of topics ranging from supergravity and baryogenesis to compact stars and the large scale structure of the Universe. A summary of some of the subject areas in which collaborations were initiated during WHEPP-5 is presented below.

This is a summary of the activities of the working group on cosmology at WHEPP-X. The three main problems that were discussed at some length by the group during the course of the workshop were (i) canceling a `large' cosmological constant, (ii) non-Gaussianities in inflationary models and (iii) stability of interacting models of dark energy and dark matter. We have briefly outlined these problems and have indicated the progress made.

This is the report of the cosmology and astroparticle physics working group at WHEPPXI. We present the discussions carried out during the workshop on selected topics in the above fields. The problems discussed concerned axions, infrared divergences in inflationary theories, supersonic bubbles in a first-order electroweak phase transition, dark matter, MOND, interacting dark energy, composite Higgs models and statistical anisotropy of the Universe.