The first study compared 30 juvenile firesetters with a control group of 15 children matched for age, sex, and intelligence, who had never set a fire. Both groups were in a residential treatment center or in an associated diagnostic center. The second study analyzed test data from 20 additional firesetters and 20 matched controls in two centers. Both studies analyzed the psychological test protocols of the children for the presence or absence of 31 variables that have proved important in the clinical literature of firesetting. Chi-square analysis was performed on the 31 variables to determine group differences. The second study confirmed the earlier study's identification of the following factors in firesetting: maternal rejection, anger at the father for his absence, abandonment or abuse, oral dependency, revenge fantasies, gaining mastery or control over adults, sexual excitement, impulsivity, projection of fire or explosion content, sadistic or destructive themes, inadequate superego development, and conduct disorder. Suggestions for further research are offered.