In this chapter, the author compares female serial killers (FSKs) and male serial killers (MSKs) and describes crime location differences as well as victim differences. Most MSKs targeted at least one stranger, whereas only a small percentage of FSKs did. In contrast, most FSKs killed someone they knew or were related to, whereas less than half of MSKs killed someone they knew, and only a few killed someone to whom they were related by blood or marriage. MSKs were 18 times more likely to stalk victims. FSKs most frequently killed males and females, but MSKs most frequently killed females. Serial killers did not commonly target only their same gender. FSKs’ most frequent method of killing was poisoning, whereas MSKs’ most frequent method was asphyxiation. There were some murder method commonalities. The author discusses her general observations of FSKs vs. MSKs and provides preliminary new data comparing serial killer taking of crime trophies. The cases of MSKs Robert Yates and Jerome Brudos illustrate stark differences in MSK crimes compared to FSK crimes and illustrate psychological concepts.