Weight counseling for adults is uncommonly performed by primary-care providers (PCPs), despite recommendations. In order to design effective primary-care interventions, a full understanding of the epidemiology of weight counseling in primary care is needed. Our objective was to measure the frequency of weight counseling at the level of the PCP. We performed a cross-sectional study of 21 220 US adult outpatient primary-care visits with 954 PCPs in 2007-2008, using data from the National Ambulatory Medical Care Survey (NAMCS). Most (58%) PCPs performed no weight counseling during any patient visits. A total of 85 (8.9%) PCPs provided 52% of all weight counseling and were categorized as 'positive deviant' (PD) physicians. Patients seeing PD physicians were older, less likely to be female and more likely to have hypertension, diabetes and obesity. Adjusting for patient characteristics strengthened the association between PD status and receipt of weight counseling during visits (adjusted odds ratio=13.2 (95% confidence interval 11.5-15.7)). In conclusion, a minority of PCPs provide the majority of primary-care weight counseling in the United States. Studies of these PCPs may help to identify practical methods to increase weight counseling in primary-care settings.