The authors report three nephroblastoma's cases occurred in adult and treated at Ibn Rochd Oncology Center at Casablanca. The average of age was 24 years (19-29 years) and the delay of diagnosis was five months (3-8 months). The most frequent clinical sign was a lumbar fossa mass. At diagnosis, radiological exams revealed that patients presented an advanced stage and metastatic disease in one case. The treatment was a total nephrectomy with ganglioma dissection when the tumor was resectable followed by chemotherapy and radiotherapy. Two patients was in progressive disease despite treatment, and one patient was lost at follow-up. The prognosis of adult's nephroblastoma remains very severe, due to the advanced stage at diagnosis and the mediocre reply to the treatment.