The importance of silicone foams has grown with unusual speed in the last ten years. Silicone provides the perfect balance of mechanical and chemical properties required in many of today’s most demanding applications. Foamed silicone production includes two parallel processes: crosslinking and foaming reactions. However, there are only few studies on silicone foaming and most of these foam silicones have large cells (>10µm) with a very low cell density (<10^9 cm-3). Consequently, can we hope to control the foaming process in terms of nucleation and cell growth? Our objective will be to discuss this specific behavior of silicone foaming compared with usual polymers foaming. Different strategies will be reviewed and explained from literature results and our own works. Typically, we will compared silicone foaming from hydrosilylation reaction (H2 foaming) and silicone foaming by supercritical C02.