Work integration for people with mental illness is complex and difficult. For those who obtain employment, job tenure is typically brief. The purpose of this article is to identify the personal determinants of job tenure of people with severe mental illness registered in prevocational programs. Out of 105 people with mental illness who are employed during the nine month follow-up after their registration in a prevocational program, close to 50 % kept their first job. According to the job tenure indicators (first or last job obtained), the results from survival analyses show that the significant variables are related to background characteristics (financial aid), work-related characteristics (length of absence from the workplace, type of job), cognitive (executive functions), and clinical aspects (paranoid symptoms). In conclusion, the authors propose not only to assess personal variables to better understand the work integration process for people with mental illness, but also to conduct a systematic evaluation of the job site.