The purpose of this report was to improve upon earlier factor analyses of obsessive-compulsive disorder (OCD) symptom categories by minimizing the heterogeneity in the aggressive obsessions category. An exploratory factor analysis was conducted on data from 293 adults with primary OCD. The resulting five factors (Symmetry/Ordering, Hoarding, Doubt/Checking, Contamination/Cleaning, and Taboo Thoughts) are phenomenologically more homogeneous than prior category-based factors and are consistent with those derived in previous item-level analyses.