Objective: To study microcrystalline cellulose II (MCCII) as new pelletization aid using the extrusion/spheronization technology.Methods: The effect of the spheronization rate and spheronization time was assessed by a response surface design. The shape descriptors and physical properties of pellets were taken as response variables. Approximately, 30 g of MCCII were hydrated, passed through a # 20 mesh sieve and spheronizated at frequencies of 6, 9 and 12 Hz and residence times of 15, 240 and 480 s in 9 experimental runs. In a separate experimental set, moisture levels of 25, 50, 75, 100 and 125% were employed at the optimal operating conditions of 6 Hz and 480 s. A microscopy analysis was used to evaluate the shape descriptors. Pellets properties such as compressibility, friability,... porosity, strength, flow rate and mass were also evaluated.Results: Pellets having a small size and a high value of shape descriptors related to morphology were obtained employing a spheronization rate and spheronization time of 6Hz and 480s and 100% wetting level. The spheronization time increased pellet densification but decreased the total porosity. Pellet mass was also favoured by using high spheronization rates. A high moisture level (>100%) rendered pellets having a large size, mass, low porosity and good yield. Conversely, pellet size decreased as sample load increased, whereas porosity and compressibility increased as sample load augmented.Conclusion: MCCII offers the potential for use as an alternative pelletization agent rendering pellets having a good flowability, high mechanical strength and low friability at the optimal operational conditions.