There has been increasing interest in the research and development of natural materials to provide alternatives for biodegradable packaging. Sugarcane bagasse is obtained from renewable resources, is low cost and abundant in Brazil. The properties of sugarcane bagasse foams’ products vary with the moisture content of the bagasse and its fiber sizes , the additives used in the formulations, such as plasticizers, mineral fillers, others. Nanoclays and calcium carbonate have been reported to improve the mechanical strength of biopolymers [1,2]. The purpose of this work was to study the influence of montmorillonite and calcium carbonate as fillers on the mechanical and biodegradation (by mass loss and release of CO2) properties of sugarcane bagasse foams. The formulation containing calcium carbonate provided a slightly faster biodegradation by mass loss in relation to that containing montmorillonite. Concerning the mechanical tests, foams formulated with montmorillonite as a complementary filler , for example, exhibited higher compressive strength results than those formulated with calcium carbonate as the same aim. In a general way, both mineral fillers have influenced positively on the physicochemical properties of the foams obtained by thermopressing process.