Six sites of the California Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) participated in a staff wellness pilot intervention designed to improve staff self-efficacy in counseling WIC clients about childhood overweight. A pre-post test design with intervention and control groups was used; outcome measures included staff perceptions of the intervention's effects on the workplace environment, their personal habits and health beliefs, and their counseling self-efficacy. Intervention site staff were more likely to report that the workplace environment supported their efforts to make healthy food choices (P <.001), be physically active (P <.01), make positive changes in counseling parents about their children's weight (P <.01), and feel more comfortable in encouraging WIC clients to do physical activities with their children (P <.05).