The effects of the binder amount and particle size on the quality and mechanical agglomeration of pellets produced from three biomasses of agroindustrial crops (rice husk, "RH"; coffee husk, "CH"; and palm rachis, "PR") were studied. Pellet quality parameters, such as the production yield, bulk density, pellet size distribution (length), water resistance, impact resistance, and ultimate and proximate analyses, were analyzed according to the European standards and were related to a possible energy exploitation. In addition, pellet morphology was evaluated by scanning electron microscopy and stereoscope visualization. The connectivity between the biomass particles is explained by mean of mechanical interlock for PR, whereas for CH and RH, a combination of mechanisms, such as adhesion and interparticle attraction forces, provides the connectivity between the biomass particles. The results showed that, for the smallest particle size analyzed (0.6 mm), pellets from laminar-shaped biomasses (RH and CH) showed a high impact resistance and water resistance. Likewise, pellets from the fibrous biomass (PR) showed a high impact resistance but a low water resistance.