This study evaluated the effects of spheronizer load and speed on the size, circularity, microporosity, compressibility, and friability of pellets prepared by extrusion-spheronization of wet microcrystalline cellulose (MCC) masses with a water content shown by mixer torque rheometry to ensure maximum consistency. Two MCC grades with different mean particle size were used. Both gave pellets with good particle size, sphericity, and compressibility, under a wide range of spheronization conditions. Modification of pellet properties of interest (including size and porosity) was possible by adjustment of spheronization conditions and MCC grade; in particular, pellet porosity was greater with MCC of larger particle size.