Objective: The Mitochondrial Lon protease, LonP1 is a major regulator of mitochondrial metabolism. LonP1 has also been implicated in human aging and diseases. We investigated the LONP1 expression in visceral adipose tissue associated with obesity. Methods: We obtained omental adipose tissue from 48 females with normal glucose tolerance undergoing gynecologic surgery. We examined the mRNA expression of LONP1 in visceral adipose tissue using quantitative RT-PCR, and performed correlation analysis of this expression with the clinical characteristics of the subjects. We also performed western blot analysis of LONP1 expression in the adipose tissue of the patients with highest body mass index (BMI) compared with the adipose tissue of the patients with lowest BMI Results: The mean age of study subjects was 42.5 ± 5.8 years old and mean BMI was 23.4 ± 3.5 kg/m². The LONP1 mRNA level was significantly positively correlated with BMI (r = 0.308, p = 0.05), but not with age (r = -0.007, p = 0.964) or HOMA-IR (r = 0.211, p = 0.185) In the western blot, the LONP1 expression was increased in the adipose tissue of patients with highest BMI compared with the adipose tissue of patients with lower BMI. Conclusion: The LONP1 was increased in the visceral adipose tissue of obese human. The clinical implication of the increased LONP1 expression in the obesity needs to be clarified by further studies.