This article seeks to model criminal career length using data from six different birth cohorts born between 1953 and 1978, totaling more than 58,000 males and females from England and Wales. A secondary aim of this article is to consider whether information available at the first court appearance leading to a conviction is associated with the length of a criminal career. Four key findings emerged. First, one can estimate career length from variables available at the first court conviction. Second, the risk of desistance remains constant during a period of 20 to 25 years if the offender does not immediately stop after the first conviction. Third, the most significant variable is age at first conviction. Finally, gender differences and birth cohorts are also important.