Despite the growing epidemic of extreme obesity in the United States, weight management is not adequately addressed in primary care. This study assessed family physicians' practices and attitudes regarding care of extremely obese patients and factors associated with them. A cross-sectional, self-administered survey was mailed to 500 family physicians in New Jersey (NJ) during March-May 2008. Measures included knowledge, weight management approaches, attitudes toward managing obesity, challenges with examinations, availability of supplies, and strategies to improve care. Response rate was 53% (N = 255). Bariatric surgery and weight loss medications were infrequently recommended, particularly in physicians with higher volume of extremely obese patients (odds ratio (OR) 0.38; 95% confidence interval (CI) 0.23, 0.62 and OR 0.51; 95% CI 0.31, 0.85 for surgery and medications, respectively). Higher knowledge was associated with increased frequency of recommendations of weight loss medications (P < 0.0001) and bariatric surgery (P < 0.0001). There was a high prevalence of negative attitudes, particularly in younger physicians and those with lower patient volume. Increased knowledge of weight-loss diets was associated with less dislike in discussing weight loss (P < 0.0001), less frustration (P = 0.0001), less belief that treatment is often ineffective (P < 0.0001), and less pessimism about patient success (P = 0.0002). Many providers encountered challenges performing examinations on extremely obese patients. More education of primary care physicians, particularly on bariatric surgery, specific examination techniques, and availability of community resources for obese persons is needed. Further research is needed to determine if interventions to increase knowledge of physicians will lead to less negative attitudes toward weight loss and extremely obese patients.