Background: Parasitic diseases are medically important, especially among immunocompromised patients. Recently, diabetes mellitus (DM) has become one of the most important clinical diseases, and the combination of this disease with parasitic infections can result in serious consequences. Objectives: The aim of this study was to evaluate the infection of intestinal parasites in patients with DM and compare them with healthy individuals in Fasa city and surrounding health centers. Methods: In this case-control study a total of 501 patients and healthy individuals (254 patients with DM and 247 healthy controls) referred to health centers in Fasa, Fars province. Fecal specimens of all of these individuals were collected in a special container. These specimens were investigated using direct smear, concentration method, acid-fast and trichrome staining, agar plate cultivation, and Baermann technique. Results: In this study, 254 diabetic patients (50.7%) and 247 (49.3%) healthy controls were included. The age range of these people was between 25 to 89 years old, with an average age of 57.7 ± 10.7. Our findings revealed that the frequency of intestinal parasites in the control group (18.6%) is higher than the patient group (12.6%). Conclusions: Although the frequency of intestinal parasites in the control group was higher than the patient group, this does not reduce the importance of preventative programs for these patients. Considering the significant effect of unpurified water on intestinal parasites, it is better to consider this issue more in health programs.