In search of guaranteeing global energy requirements, waste from different agricultural, forestry and industrial sources is presented as a renewable and sustainable energy source. The manufacture of solid fuels from biomass based on the densification of this to improve its mechanical and energy properties is one of the mechanisms of viable energy production from the technical-economic point of view. The biomass mixture is one of the topics currently researched, in which various factors can affect the final behavior of the briquettes. In this research the influence on the mechanical properties of briquettes obtained from the mixture between two biomasses is studied: rice husk and pine sawdust. A mixed factorial experimental factorial design is used, in which the process temperature, the proportion of the rice husk biomass over the total mass, and the compaction time are defined as experimental factors. Experimental statistical models are obtained that partially explain the behavior of several responses that characterize the mechanical properties of the briquettes based on the selected independent parameters. It was found that the mechanical durability of the briquettes is higher than 97.5%, meets the existing standards, like German Institute for Standardization (DIN) 51731, Theological Institute Batista Ebenézer (ITEBE) SS187120 or International Organization for Standardization (ISO) 17225-2, for a compaction temperature of 110 °C and a proportion of rice husk that does not exceed 60% of the total biomass mixture in the briquette. The compaction time was also statistically significant to achieve a briquettes density and an appropriate elasticity modulus in the briquettes. The results of this research are of interest and can serve as a starting point for the design of the industrial process of densification of these two mixed biomasses.