ABSTRACT Background: Various studies have defined the existence of pancreatic exocrine insufficiency (PEI) in diabetic patients. The concentration of faecal elastase-1 (FE-1) has long been used as a screening method for exocrine pancreatic activity, with good results when compared to direct methods. The prevalence of pancreatic exocrine insufficiency in Egyptian diabetic patients measured by FE-1 concentration is still unknown. Objective: To investigate the prevalence of PEI in Egyptian diabetic patients, and to examine its relationship with the degree of glycemic control and other metabolic parameters. Patients and Methods: In this cross-sectional study, 180 diabetic patients, were divided into two equal groups. Group I: patients with type 1 diabetes mellitus (T1D) and Group II: patients with type 2 diabetes mellitus (T2D). Other 90 healthy subjects were enrolled in the study as a control group (Group III). All participants were evaluated for PEI by measuring the FE-1 concentration through the enzyme-linked immunosorbent assay (ELISA) method. Patients having FE-1 concentration < 200 μg/g of stool were diagnosed with PEI. Results: The prevalence of PEI was 35.6% in T1D, 31.3% in T2D, and 7.8% in the control group (P < 0.001). A significant negative correlation was observed between FE-1 levels and both FBS and HbA1c in diabetic patients. There was also a significant positive correlation between body mass index (BMI) and FE-1 concentration for T1D and T2D groups. Conclusion: Significant PEI was observed in Egyptian T1D and T2D patients assessed by the FE-1 concentration test.