Developed and gathered initial psychometric data on a new self-report measure of adolescent social functioning. The Checklist of Adolescent Problem Situations (CAPS) is a 75-item checklist designed to identify the situational sources of social inadequacy. The CAPS contains seven factor-analytically derived scales: Parents, Siblings, School, Make Friends, Keep Friends, Problem Behavior, and Work. Reliability analyses indicate that CAPS scales are both internally consistent and stable over a 2-week period. Scores on the CAPS varied as a function of subjects' grade and sex. Adolescents who were unpopular and reported heightened conflict with parents scored significantly higher on the CAPS than popular and low-conflict adolescents.