Background: To investigate visceral adiposity index (VAI) levels in obese patients with and without metabolic syndrome (MetS) and its relationship with insulin resistance (IR), and define cutoff value of VAI in the determination of patients with MetS and IR. Methods: Aged between 18 and 65, 92 patients with obesity were included. Levels of homeostasis model assessment of IR (HOMA-IR) and VAI were calculated. Results: Of 92 patients, HOMA-IR and VAI levels (P < 0.001 and P < 0.001, respectively) were found to be higher in 41 (44.6%) with MetS. The cutoff value of VAI in predicting MetS was found to be 2.205. The frequency of MetS was seen as 22.2% when VAI was below this value, but if over, was found to be 66%. There was a positive correlation between VAI and HOMA-IR levels. In 36 cases (39.1%) with HOMA-IR (≥2.5), VAI was detected to be higher than those without IR, and high-density lipoprotein-cholesterol levels were lower. The cutoff value of VAI in predicting IR was found to be 2.31. While the prevalence of IR was 23.4% in those with VAI of 2.31, IR frequency in patients with equal to or greater than 2.31 was determined as 55%. Conclusion: We found that MetS was present in almost half of overweight and obese individuals, and the cutoff values of VAI in predicting the presence of MetS and IR were 2.205 and 2.31, respectively. Our study was carried out in overweight and obese Turkish individuals, and we consider that further studies including normal weight individuals and larger population are required.