Cyclospora cayetanensis one of the coccoidian parasite which presenting by gastrointestinal symptoms like prolonged wet diarrhea, abdominal pain, anorexia, weakness and nausea gastrointestinal diseases. Infections are mostly seen in immunocompromised hosts such HIV/AIDS patients. The clinical spectrum of the diseases can vary from asymptomatic infection to life-threating infections in immunocompromised patients. Differantial diagnosis should be made carefully and proper antibiotic treatment should be given in symptomatic cases. It should pay attention to distinguish C. cayetanensis from Cryptosporidium cysts on stool exams especially. In our study, 22 and 88 years-old symptomatic male patients with C. cayetanensis infection had been presented. Diagnosis is made by modified Ziehl-Neelsen staining and ultraviole microscopy in addition to direct microscopy in our patients. Both of the patients had no history of travel and antibiotic consumption however young patient had fast-food habits. Anti-HIV antibodies were found as negative in sera samples. Our patients were evaluated as immunocompetent individuals. The patient which had prolonged symptoms been treated successfully by trimethoprim-sulphametoxazole (TMP-SMX) 2 x 160/800 mg/day orally during one week. In other patient, succesfull response was achieved by moxifloxacin 1 x 400 mg/day IV which mainly starting for treatment of cellulitis and the treatment was continued for one week. Cyclopora cayatensis cycts were completely disappeared on control stool examinations in addition to improvement of clinical findings in our cases. Relapse was not observed in the three month follow-up of patients. C. cayetanensis should also take into consideration for immunocompetent patients with complaint of enteritis or nausea, abdominal pain. If these patients have prolonged complaints they should also treat such as immunocompromiseds.