Background: A new data base system was applied to analyse our patient group with two aims: (a) to analyze the effects of former cryptorchidism on the fertility of our infertility patients in comparison with the data of the literature and (b) to evaluate this system in a clinical study. Materials and Methods: Using the electronic data base Winsperm 2000®, 1,648 infertility patients, 79 patients with testicular cancer and 201 healthy semen donors were examined. Results: A history of cryptorchidism, treated at 6.8 ± 3.3 years of life, was found in 10.1% of our infertility patient group. The routine spermiogram parameters, as well as basal hormone concentration of FSH, LH and testosterone, differed significantly from those of the healthy semen donor group. Comparison between patients with former unilateral and bilateral cryptorchidism differed significantly only in total sperm count. 27.7% of patients with a history of unilateral and 5.4% of patients with a history of bilateral cryptorchidism showed a sperm concentration within the normal range (p < 0.01). Azoospermia was detected in 13.1% of patients with unilateral cryptorchidism and in 29.7% of patients with former bilateral cryptorchidism (p < 0.05). The patients responding to our conception questionnaire realised a total conception rate of 46.1% in the ‘non-cryptorchidism group’ and of 20.6% in the ‘cryptorchidism-group’ (p < 0.05), whereas the conception rates did not differ between former unilateral and bilateral cryptorchidism (p > 0.05). Sixteen (20.3%) of the 79 patients with testicular neoplasm were previously treated for cryptorchidism. Conclusion: The results of our patient group underline the significance of former cryptorchidism for infertility and testicular neoplasm. The new data base system facilitates rapid data retrieval and examination.