Aim: To evaluate the association between elevated body fat percent (BF%) and the prevalence of insulin resistance (IR) in the adult population with body mass index (BMI) in the normal values. Methods: We carry out an analytical cross-sectional study. The participants attended outpatient from 2012 to 2016 in a private clinic in Lima-Peru between 18 and 60 years with a BMI between 19 and 24.9/Kg/m2. We defined elevated BF% if the values were greater than 25% in men and 30% in women and IR with a cut-off point of HOMA-IR based in the 75th percentile. We performed a generalized linear model from family Poisson (crude and adjusted) with robust standard errors to evaluate the association between BF% and the IR. We reported as association measure the prevalence ratio (PR) with their respective 95% confidence intervals (CI). Results: We included 284 participants, the average age was 33.77 ± 10.86 (SD) years and the percentage of women was 88.1%. The prevalence of elevated BF% was 71.13% and the prevalence of IR was 25%. We found an association between the elevated BF% and IR, PR = 3.17; 95% CI: 1.46–6.91. Conclusions: Body fat percentage seems to be a good indicator of IR in patients with normal BMI and without endocrine comorbidities. Longitudinal prospective studies are recommended to corroborate our findings.