Research related to the importance of involving parents directly in treatment programming for childhood obesity has provided inconclusive results because of methodological problems and relatively short treatment duration periods. The effectiveness of an extended behavioral weight control program was evaluated during a 10-week treatment phase and at one- and three-month follow-ups. Three treatment conditions were compared: (1) parent only (P), where the treatment instructions were given to the parent alone; (2) child only (C), where the treatment instructions were given to the child alone; and (3) parent and child together (PC). A no-treatment control group was also assessed for 10 weeks. Although all treatment groups lost an average of at least 6 pounds over the 10-week period, there were no significant dlfferences between the three groups in mean weight loss. There was a trend, however, for greater loss in the PC group, followed by the C group and the P group. This pattern was generally maintained at the three-month follow-up. (Author)