At the University Hospital in Lund, Sweden, a preparation program was developed for children undergoing lumbar punctures (LPs) during chemotherapy for leukemia or lymphoma. Subsequently, a study was initiated to determine whether a preparation program for children prior to treatment would reduce their anxiety and improve their cooperation. This study also was undertaken to examine whether reinforcing the preparation information prior to each LP would be beneficial. The 30 children who participated in the study were divided into three groups: a control group whose members did not receive preparation and two other groups whose members were exposed to different numbers of preparation programs. The parents and the nurse in charge evaluated the children's reactions during treatment using two 6-point rating scales: an anxiety scale and a noncooperation behavior scale. Two unbiased, trained observers later viewed video recordings of the children's reactions and evaluated them using the same tools. In addition, each child rated his or her experience of pain on a 10 cm visual analogue scale. Based on these ratings, the groups were analyzed to determine if within-group differences existed from one treatment to the next and to determine if between-group differences existed at the various times of treatment. Few statistically significant differences were found, but the results indicate that the children in the most informed group exhibited sustained reductions in their perceptions of pain. This may signify that reinforcing the preparation information before each of the LPs enabled these children to cope with the pain more effectively.