Abstract. Dark matter (DM) could consist of very light bosons or axion-like particles which can be basically described as a classical scalar field that experience oscillations. The presence of the DM field can lead to observable effects on the dynamics of ordinary matter, either because the DM stress tensor modifies the spacetime metric, or if the DM is directly coupled to the Standard Model. In this talk I will summarise recent work where the exquisite precision of measurements of orbital parameters of binary pulsars is exploited to constrain the effects.