Simple renal cysts in childhood are uncommon and often are confused with duplication anomalies or renal malignancy. A review of 20 children with simple renal cysts at our institution has documented the spectrum of clinical presentations and radiographic findings of this unusual renal mass. Surgical exploration and marsupialization of the cyst wall were done in 12 patients, 4 underwent nephrectomy earlier in our series and 4 have been followed conservatively by ultrasonography or computerized tomography scanning. Although equivocal cases necessitate surgical intervention, we advocate conservative therapy with diagnostic ultrasonography with or without cyst puncture in asymptomatic and normotensive children with simple renal cysts.