This report presents the results of a study to examine the feasibility of using volunteers as research staff for a randomized trial of whether reduction in dietary fat intake could prevent or delay breast cancer recurrence. We examined whether volunteers could be trained to recruit study participants, deliver a complex and intensive dietary intervention, and monitor intervention effectiveness. Volunteers, who were mostly employed nurses and dietitians, screened 521 women, of whom 293 were eligible and 144 were randomized. Participants were postmenopausal women under age 75, who had recently been diagnosed with breast cancer and treated with either mastectomy or lumpectomy. At 1 year postrandomization, 77% of intervention and 75% of control participants remained active in the study. Intervention effects (change in intervention group minus change in control group) at 3, 6, and 12 months postrandomization were 5.9, 8.4, and 7.2% energy from fat and 1.7, 3.0, and 3.5 kg body weight (all P < 0.001). These results were similar to those from other studies that used paid, professional staff to deliver and monitor interventions. Results from this feasibility study suggest that volunteer-based health organizations can provide research opportunities for health practitioners and can conduct high-quality research at lower costs.