Introduction: The high prevalence of overweight and obesity threatens the health and safety of the fire service. Healthcare professionals may play an important role in helping firefighters achieve a healthy weight by providing weight loss counseling to at-risk firefighters. This study characterizes the impact of healthcare professional weight loss advice on firefighter weight perceptions and weight loss behaviors among overweight and obese male firefighters. Methods: A national sample of 763 overweight and obese male firefighters who recalled visiting a healthcare provider in the past 12 months reported information regarding healthcare visits, weight perceptions, current weight loss behaviors, and other covariates in 2011-2012. Analyzed in 2013, four unique multilevel logistic regression models estimated the association between healthcare professional weight loss advice and the outcomes of firefighter-reported weight perceptions, intentions to lose weight, reduced caloric intake, and increased physical activity. Results: Healthcare professional weight loss advice was significantly associated with self-perception as overweight (OR=4.78, 95% CI=2.16, 10.57) and attempted weight loss (OR=2.06, 95% CI=1.25, 3.38), but not significantly associated with reduced caloric intake (OR=1.26, 95% CI=0.82, 1.95) and increased physical activity (OR=1.51, 95% CI=0.89, 2.61), after adjusting for confounders. Conclusions: Healthcare professional weight loss advice appears to increase the accuracy of firefighter weight perceptions, promote weight loss attempts, and may encourage dieting and physical activity behaviors among overweight firefighters. Healthcare providers should acknowledge their ability to influence the health behaviors of overweight and obese patients and make efforts to increase the quality and frequency of weight loss recommendations for all firefighters. (C) 2015 American Journal of Preventive Medicine