Posterior urethral valves (PUV) are the most common cause of lower urinary tract obstruction in male infants. Setting the diagnosis of PUV and finding the appropriate treatment is challenging job for physicians. We present a case of 6 weeks old male infant with PUV treated in our hospital. We will present you the means by which the diagnosis was set and how was the treatment carry out. With this patient we had several diagnostic and therapeutically difficulties that give particularity to this case and, in our opinion, can be instructive for other physicians.