Appropriate sedation of pediatric oncology patients during painful diagnostic and therapeutic procedures is a recognized problem. At the Memorial Sloan-Kettering Cancer Center the pediatric oncologists and anesthesiologists have developed a cooperative program that has provided safe and effective sedation of outpatients. The experience with 100 consecutive outpatients is reported. Patients ranged from 3 months to 17 years of age. Procedures included lumbar puncture and/or intrathecal chemotherapy, multiple bone marrow aspirations, bone marrow biopsies, and removal of indwelling central vein catheters. Monitoring of patients during the procedures as well as various pharmacologic techniques to provide adequate working conditions are described.