Serial murder is a genre of crime that has received a great deal of media and academic attention, yet, serial murder committed by women has only begun to garner a portion of this attention within the last 15 years. This study examines the reliability of Kelleher and Kelleher's classification rubric, the only classification system developed for female serial murderers, as well as considering Hickey's classification of serial offenders by location. Other variables associated with homicide research have also been examined to determine their roles in both these crimes and classifying offenders. The current research will demonstrate that offender motivation is not an ideal basis for the classification of female serial murderers, who tend to defy simple or singular classification within existing typologies. The other variables analysed indicate that victim–offender relationship and victim approach are important to understanding these female offenders and their crimes, as well as the possible development of more accurate classification systems. Copyright © 2013 John Wiley & Sons, Ltd.