Study of the J/psi suppression in In-In collisions at the CERN SPS The NA50 experiment has shown that the J/psi production in Pb-Pb collisions is anomalously suppressed with respect to the yields extrapolated from proton-nucleus interactions. The NA60 experiment has recently taken data on J/psi production in In-In collisions. The comparison of the suppression patterns in the two systems (In-In with respect to Pb-Pb) should help in understanding which is the physics variable driving the J/psi suppression (L, Npart, energy density). I will present the preliminary NA60 results on charmonia production and I will discuss their implications on our understanding of the anomalous J/psi suppression.