Little is known about the criminal careers of female sex offenders. A meta-analysis by Cortoni, Hanson and Coache revealed that about 1.5% of female sex offenders re-offend sexually. Even less is known about the extent to which female sex offenders' criminal careers contain sex offences as well as other offences, i.e. the extent of specialisation in sex offending. This study examines the criminal careers of all female sex offenders prosecuted by the criminal justice authorities in the Netherlands in the period 1994-2005. A latent class analysis shows that three subgroups of women can be distinguished: once-only offenders (who commit just one sex offence and no other offence), generalists (who combine sex offending with relatively many serious other, often violent, offences) and specialists (who commit relatively many sex offences next to some minor offences). Women in these three criminal career types differ in characteristics such as victimisation history, alcohol abuse and the sex of the victims. © 2011 National Organisation for the Treatment of Abusers.