The equivalent packing size of spheroidal particles is studied microscopically. It is done based on the structural results obtained by means of discrete element method. The packing similarity between spheres and spheroids is first established in terms of coordination number, the most popular microscopic parameter associated with packing structure. It is then shown through the analysis of the mean coordination number of each component in a binary mixture of spheres and spheroids that the equivalent packing size does exist. The results are consistent with those determined in terms of macroscopic parameters such as packing density or specific volume. The findings provide evidence to support the general application of the concept of equivalent packing size. (C) 2017 Elsevier B.V. All rights reserved.