In a variety of inflation models, the motion of the inflaton may trigger the production of some iso-curvature particles during inflation, for example via parametric resonance or a phase transition. Inflationary particle production provides a new mechanism for generating cosmological perturbations (infra-red cascading) and can also slow the motion of the inflaton on a steep potential. Moreover, such models provide a novel example of non-decoupling of high scale physics during inflation. I will discuss the observational consequences of inflationary particle production, including the generation of features in the primordial power spectrum and large nongaussianities with a unique shape of bispectrum. Finally, I will discuss various realizations of this scenario in string theory and supersymmetry.