Objective: Surgery is still proposed by some as the treatment of choice for unilateral multicystic dysplastic kidney (UMCDK) because of the potential complications of hypertension, infection and malignant change. The purpose of this study is to demonstrate that the risk of hypertension does not justify routine nephrectomy.

Material and Methods: We report 41 cases of UMCDK, treated between 1980 and 2001, 28 of whom were male (68%). Twenty‐one patients were nephrectomized (51%). Twenty patients (49%) underwent clinical and ultrasound follow‐up. Blood pressure was controlled every 3–4 months (over a period ranging from 9 months to 6 years) and an ultrasound scan was performed every 6 months during the first 2 years, and annually thereafter.

Results: In the patients treated non‐operatively we observed a progressive spontaneous involution of their multicystic dysplastic kidneys and the total absence of complications such as hypertension or malignancy.

Conclusion: It is reasonable to conservatively manage patients with UMCDK by means of repeated ultrasound examinations and blood pressure control.