Abstract The purpose of the current study was to develop and assess the efficacy of a psychological intervention program to reduce the behavioral distress of pediatric cancer patients undergoing highly-painful medical procedures (bone-marrow aspirations and lumbar punctures) which are required for the diagnosis and treatment of their disease. The psychological intervention was delivered to 5 patients ages 3 1 2 –7yr within the context of a staggered baseline design. Results suggested that the program was effective at reducing behavioral distress for all 5 patients during the initial intervention. However, 1 S showed some regression of intervention effects during a second treatment session. Possible alternative explanations for the results obtained were discussed and implications for future research were presented.