Introduction and Aims: This study aimed to examine the perceived risks and benefits of quitting in smokers diagnosed with psychosis, including potential gender differences and comparisons to smokers in the general population. Design and Methods: Data were collected from 200 people diagnosed with psychosis participating in a randomised controlled trial testing the effectiveness of a multi-component intervention for smoking cessation and cardiovascular disease risk reduction in people with severe mental illness. Results were compared with both treatment and non-treatment seeking smokers in the general population. Results: Male and female smokers with psychosis generally had similar perceived risks and benefits of quitting. Females rated it significantly more likely that they would experience weight gain and negative affect upon quitting than males diagnosed with psychosis. Compared with smokers in the general population also seeking smoking cessation treatment, this sample of smokers with psychosis demonstrated fewer gender differences and lower ratings of perceived risks and benefits of quitting. The pattern of risk and benefit ratings in smokers diagnosed with psychosis was similar to those of non-treatment seeking smokers in the general population. Discussion and Conclusions: These results increase our understanding of smoking in people with severe mental illness, and can directly inform smoking interventions to maximise successful abstinence for this group of smokers. For female smokers with psychosis, smoking cessation interventions need to address concerns regarding weight gain and negative affect. Intervention strategies aimed at enhancing beliefs about the benefits of quitting smoking for both male and female smokers with psychosis are necessary. ? 2013 Australasian Professional Society on Alcohol and other Drugs.