Although comorbid depression is a predictor of poor treatment response in obsessive-compulsive disorder (OCD), there is limited understanding of factors that contribute to depression severity in OCD. The current study examines the influence of OCD-related factors (autogenous obsessions and obsessional beliefs) and non-specific factors (avoidance and anxiety) on depression severity in a sample of OCD patients. There were 56 participants with only OCD and 46 with OCD and comorbid depression. Self-report questionnaires measuring depression, OCD-related factors, and non-specific factors were completed. Although there were no significant differences between the two groups on these variables, depression severity was positively correlated with anxiety, avoidance, obsessional beliefs, and autogenous obsessions in the whole sample. When entered into a multiple regression model to predict depression severity, these factors accounted for 51% of the variance. While OCD-related factors remained significant predictors after controlling for non-specific factors, the non-specific factors made the most significant contributions to the model. Our findings suggest that in addition to dealing with autogenous obsessions, addressing anxiety and avoidance might lead to improvements in the treatment of OCD with comorbid depression.