  We present our results on the {\gamma}-ray emission from interaction-powered
supernovae (SNe), a recently discovered SN type that is suggested to be
surrounded by a circumstellar medium (CSM) with densities 10^7-10^12~ cm^-3.
Such high densities favor inelastic collisions between relativistic protons
accelerated in the SN blast wave and CSM protons and the production of
{\gamma}-ray photons through neutral pion decays. Using a numerical code that
includes synchrotron radiation, adiabatic losses due to the expansion of the
source, photon-photon interactions, proton-proton collisions and proton-photon
interactions, we calculate the multi-wavelength non-thermal photon emission
soon after the shock breakout and follow its temporal evolution until 100-1000
days. Focusing on the {\gamma}-ray emission at >100 MeV, we show that this
could be detectable by the Fermi-LAT telescope for nearby (<10 Mpc) SNe with
dense CSM (>10^11 cm^-3).
