This study examined the effectiveness of cognitive training (the Thinking Skills for Work Program) for improving competitive employment outcomes in persons with severe mental illness who have a history of job failure. Forty-four clients receiving services at 2 inner-city community mental health agencies were randomly assigned (within each site) to receive either cognitive training and supported employment (CT + SE) or supported employment only (SE Only). Retention in the CT + SE program was high (91%). Baseline to 3-month assessments showed significantly greater improvements in neurocognitive functioning, depression, and autistic preoccupation on the Positive and Negative Syndrome Scale for the CT + SE set compared to the SE Only group. Employment outcomes over 1 year showed that clients who received CT + SE were significantly more likely to work (69.6 versus 4.8%, respectively), worked more jobs, worked more hours, and earned more wages than clients with SE Only. The findings provide support for the feasibility of implementing the Thinking Skills for Work Program in the context of supported employment and its beneficial effects on cognitive functioning and competitive employment in persons with severe mental illness.