The current study examines the role of callous/unemotional (CU) traits in response to treatment among children with conduct problems (CP) and attention-deficit/hyperactivity disorder (ADHD). Fifty-four children with CP/ADHD and 16 controls (age = 9.48, SD = 1.58) took part in a summer treatment and research program. Simple correlations showed that CU and CP were associated with a number of treatment outcome measures. When examined together in regression analyses, CU and CP were uniquely associated with three treatment outcomes each (CU-improvement in social skills and problem solving, negative behaviors in time-out; CP-time-outs per day, peer ratings, peer dislike). The implications for these findings with regard to treatment response in children with CP/ADHD with and without CU traits are explored.