The HCR-20 is widely used to assess risk of violence among patients with schizophrenia.Further understanding of the accuracy and changes over time in C and R scores is needed.Using prospectively collected data on 248 men with schizophrenia, the present study found thatthe HCR-20 significantly predicted aggressive behavior over 24 months. The H, C, R, HCR-20total, and final risk judgment scores were unable to predict aggressive behavior better thanchance among the general psychiatric patients in the first six months after discharge. Changesin three C items, the total R score, and in three R items significantly predicted changes inaggressive behavior.