The men were under the supervision of the Probation Services of two large British cities and were receiving clinical psychology services in a regional secure unit. The study examined the relationship between the SOAP and standard measures of personality, namely, the NEO Five Factor Inventory (NEO-FFI), and obsessive-compulsiveness, using the Maudsley Obsessive-Compulsive Inventory (MOCI). Factor analysis was used to reduce the SOAP to three reliable factors: emotional distress, cognitions that support sex with children, and concern for others (empathy). These factors correlated respectively with higher neuroticism and lower extroversion as measured by the NEO-FFI and greater obsessive-compulsiveness as measured by the MOCI, along with trait agreeableness, irrespective of whether or not a correction was made for socially desirable responding. When partial correlation controlled for the influence of neuroticism on the correlation between cognitions that support sex with children and the MOCI, there was no change in the association between these variables. These findings indicate that negative affect and obsessional tendencies are significant underlying influences on the feelings and behavior of sex offenders who victimize children and that the obsessiveness of the group is not attributable to neuroticism. The current study found that persons who are high in both pro-offending attitudes and social inadequacy are most obsessive. The relationship between paraphilia and obsessiveness as a maintaining factor may explain the chronic nature of sexual offending. Dealing with obsessiveness in treatment thus becomes a focus. 4 tables and 54 references