The existence of Dark Matter in the universe is one of the biggest problems in cosmology. The Cold Dark Matter (CDM) model has been able to explain in a simple manner the observed universe at big scales but it has shown some difficulties in to explain some observed phenomena at small scales in galaxies. A great effort to solve these discrepancies has been carried out in the last time. Nevertheless, there are other possibilities. In this talk we present some of the advances of the hypothesis of a Scalar Field/wave as dark matter and show that this candidate behaves exactly in the same way as CDM at big scales but it can solve some of the problems of CDM at small scales.