Simple testicular cyst is increasingly diagnosed because of the general availability of high-resolution ultrasound devices, although its management has been controversial. The authors report their experiences in managing large simple testicular cyst in two adults aged 56 and 68 years. The first patient was hospitalized with a presumptive diagnosis of left hydrocele, and the second patient was hospitalized with left simple testicular cyst. Both patients felt pain in the left scrotum. The maximum diameter of the cyst in both patients was more than 6 cm. The patients were successfully treated with orchiectomy with very good long-term results. The authors indicate that a careful study of the medical history, physical examination, and scrotal ultrasonography may facilitate an accurate preoperative diagnosis. Age, symptom, compliance with the surveillance of the patient, and the size and dynamic ultrasonographic changes of the cyst should all be considered in the selection of the treatment regimen. Such a study may be helpful in managing a simple testicular cyst.