We report a case of adenocarcinoma of the rete testis in a 44-year-old man, presented intially with a hydrocele and later with signs of infection in the affected hemiscrotum. Multiple focal lesions within the testis appeared 6 months later in ultrasounds. After high inguinal orchiectomy, histology revealed a primary adenocarcinoma of the rete testis. Adenocarcinoma of the rete testis is a rare a highly malignant tumour originating in the mediastinum of the testis. Slightly over 40 cases have been reported in the literature. The treatment of choice is radical orchiectomy. Prognosis is poor; as mainly as 40% of patients die within the first year of diagnosis.