OBJECTIVES: While previous studies have shown that overweight and obesity are associated with higher costs, less is known about health care costs by place of service (POS) at various levels of BMI. This study measures the impact of BMI as a continuous variable on health care cost at different places of service. POS categories include: pharmacy, doctor’s office, inpatient hospital, outpatient hospital or clinic, emergency department, laboratory, and other. METHODS: Using 2003-2012 retrospective data from large employers throughout the United States, employees’ BMI values were calculated using health risk appraisal data. All study employees were >=18, had >=12 months of health plan coverage after their index BMI screening date, and had no medical claims indicating pregnancy. Employees with BMI<18 (1st percentile) or BMI>47 (99thpercentile) were excluded. Generalized additive models on 12-month post-index POS costs produced estimates of the nonlinear relationship between BMI and cost after controlling for age, gender, marital status, race, salary, zip-code region and index year. RESULTS: This study included 71,633 eligible employees; 32.0% were female. The average BMI, age and annual salary were 27.3, 39.8 years and $81,382, respectively. Costs increased significantly with BMI in each POS (P<0.001). Total adjusted annual per-employee health care cost estimates at BMI values of 25, 30, 35, and 45 were $3043, $3932, $4357, and $7248, respectively. Cost estimates by POS at these BMI values were: Pharmacy ($706, $903, $1106, $1372), Inpatient ($398, $678, $643, $2440), Outpatient ($799, $1057, $1113, $1516), Office ($939, $1044, $1174, $1495), Emergency ($131, $159, $200, $186), Laboratory ($34, $38, $46, $43), and Other ($35, $53, $74, $196), respectively. CONCLUSIONS: Employees with higher BMI levels incurred more cost at each of the 7 places of service. Because of the high prevalence of overweight and obesity, these costs represent a significant burden for US employers.