The aim of the study was to provide empirical data on the severity of hostility among methamphetamine users experiencing psychotic symptoms. Participants were 71 methamphetamine users from the general community who had experienced positive psychotic symptoms in the past year. Psychotic symptoms were defined as a score of 4 or greater on the Brief Psychiatric Rating Scale (BPRS) subscales of suspiciousness, unusual thought content, or hallucinations. The BPRS hostility subscale was used to measure hostility during the most severe symptom episode during the preceding year. Pathological hostility (BPRS score of 4+) was reported by 27% of participants during their most severe episode of psychotic symptoms. Hostility was significantly more common among participants experiencing severe psychotic symptoms (BPRS score 6-7, 42% vs. 15%) or where the psychotic symptoms continued for at least two days (43% vs. 20%). Daily heroin use and low levels of schooling were also correlated with hostility. Clinically significant hostility co-occurs with psychotic symptoms in around one-quarter of methamphetamine users who experience psychosis, and it is more common with severe psychotic symptoms that persist for longer than two days.