Obesity has been recognized as a major public health problem. It is an important risk factor for the development and progression of CKD in patients with diabetes. It also leads to significant lipid deposition within and around other tissues (ectopic fat storage), the marked increase in ectopic fat around the organs may eventually impair their functions. The aim of this work is to assess the relationship between perirenal fat thickness (PrFT) and eGFR in adult males with type 2 diabetes mellitus.  This cross-sectional study was conducted on a total number of sixty male participants, aged from 40-65 years, who were known to have type 2 diabetes according to the American Diabetes. Association (ADA 2021). They were recruited from the outpatient endocrinology clinic at Al-Zahraa University Hospital, Cairo Governorate, Egypt, during the period from June 2021 to December 2021. There was a statistically significant difference between all groups (who were classified according to Body mass index (BMI) regarding the age, weight, W.C and LDL. According to PrFT, it was found that there was statistically significant difference between the two groups regarding patients' weight, BMI, W.C, creatinine, Urinary Albumin creatinine ratio, (ACR). and eGFR. The patients' height, weight, BMI, W.C, and ACR were found to be significantly and positively correlated with PrFT, and it was significantly and negatively correlated with eGFR. Studying the predictors of PrFT, by unvariant regression analysis, revealed that height, weight, BMI, and waist circumference were the most significant predictors and that weight and W.C were superior to height and BMI. In this study, the Cutoff value of PrFT in the detection of GFR less than 60 ml/min/1.73m2, was 30.15mm, its sensitivity was found to be 72.2%, specificity 69% (AUC: 0.729), with diagnostic accuracy 70%.  PrFT was independently and negatively correlated with eGFR, suggesting a possible role of PrFT in kidney dysfunction in T2DM patients. Patients that had impaired kidney functions had large PrFT. Patients that had PrFT >30.15ml had higher W.C, BMI, creatinine and ACR. Perirenal fat thickness had positive correlation with BMI, WC and ACR. The most predictive factors for PrFT were weight and W.C. According to ROC curve, the diagnostic Cutoff value of PrFT in detection of GFR less than 60 ml/min/1.73m2, was 30.15mm, its sensitivity was found to be 72.2%, specificity 69% (AUC: 0.729), PPV =50%, NPV= 85.3%, with diagnostic accuracy 70%.