High attrition rates in large-scale clinical trials can ultimately result in decreased statistical power. WINS is a randomized trial with a recruitment goal of 2,500 women, evaluating the influence of dietary fat intake reduction on breast cancer recurrence, conducted at 38 clinical sites. To date, WINS has enrolled 1735 participants, with a 7.7% “inactive” rate (56% low-fat intervention group, 44% control group). Reasons for attrition include: unable to contact/not interested (23.8%), other medical/family problems (16.4%), caring for sick relative (9.7%), cancer recurrence (8.9%) (participants with a recurrence are encouraged to remain in the trial), too busy (7.5%), and wanted to be in the intervention group (7.5%). In response to an identified need to implement behaviorally oriented retention strategies study-wide, local and centralized procedures were developed by the WINS Intervention Unit (IU). Working with all clinical sites, the IU facilitates ongoing communication and development of local action plans for retention problems. In addition, the IU identifies “inactive” participants refractory to local clinic strategies, collects background information on such participants from clinical site Nutritionists, and via telephone, implements retention strategies by a behaviorally trained Nutrition Intervention Coordinator (NIC). During this contact, the NIC discusses participant's concerns and attempts to negotiate a compromise resulting in study continuation, such as taking “time-off” from the study or participation in a modified capacity. Following recent implementation, approximately 2-4 participants/month have been identified as candidates for this intervention. Data collection procedures are in place to evaluate effectiveness. A centralized IU can be used to develop local retention action plans and deliver behaviorally oriented telephone interventions in a large-scale clinical trial. The effectiveness of this approach is currently under evaluation.