Purpose: Obesity as a systemic risk factor associated with implant failure or other complications has not been studied. The aim of this study was to compare the frequency of implant failure and complications between obese and nonobese patients. Materials and Methods: Charts from 220 partially edentulous patients with 321 implants were examined for demographic information, medical health history, diabetes, smoking, patient-reported height and weight, periodontal status (no, mild, moderate, or severe periodontitis), tooth number, date of the implant and prosthesis placement, and treatment notes pertinent to the complications or failure. Subjects were classified according to their body mass index (BMI) as normal (18.5 to 24.5 kg/m²), overweight (25 to 29.9 kg/m²), or obese (≥ 30 kg/m²) based on self-reported height and weight. Variables including sex, smoking, diabetes, and periodontal condition were considered as confounders. Data were analyzed to examine differences in frequency of complications and occurrence of failures. Results: Implant failure was low (2.1%) and did not differ by BMI category. Compared with normal BMI patients, obese patients had increased odds of experiencing an implant complication (OR = 4.9, 95% CI [1.4, 17.6]) after adjustment for other variables. Diabetes was not associated with an increased risk of complications; obese patients with diabetes had decreased odds of an implant complication compared with obese patients without diabetes. Conclusion: No association was observed between obesity and implant failures. BMI category was associated with implant complications; obese patients have greater odds of experiencing implant complications postsurgically. Treating obese patients with the existing protocol for diabetic patients (antibiotic regimens, more frequent follow-up, and maintenance appointments) may improve clinical outcomes. Schlagwörter: clinical outcomes, dental implants, obesity, systemic risk factors