Lack of the testis is an important factor in psycho-sexual development of the boys, and implantation of the prosthesis plays a very essential role in the treatment of that group of patients. Currently there are no standards regarding when prosthesis should be implanted, and which access is connected with minimal rates of complications. We present our experience of primary prosthesis implantations in boys treated in our department.From 2000 to 2014, primary implantation of the testicular prosthesis was performed in 290 boys. The early and late post-operative complications and long-term therapeutic results were analyzed, considering age at the time of implantation, the time between the initial operation and implantation of the prosthesis, and the surgical approach.Best results were observed in 267 patients and bad outcome in 23 patients. Prosthesis implantation in young boys operated within the first three years of life or during the first year after primary surgery was connected with statistically fewer complications (P = .002 and P < .05, respectively). Supra-scrotal access was connected with the lowest rate of complications (P = .01).Long-term therapeutic results in boys with testicular prostheses were good in the majority of cases. Implantation of the first prosthesis should be performed early between 1 and 3 years of life in boys with lack of the testis. Implantation of a prosthesis should also be performed within 1 year after removing of testis or during orchiectomy. Supra-scrotal access should be chosen for testicular prosthesis implantation due to the best long-term results.