Background:  Patients with malignancy (n = 130) participated in the sperm cryopreservation program. Methods:  After washing and concentrating, sperm was cryopreserved using KS-VIm cryoprotectant medium. Participant background factors such as age, marital status, underlying disease, presence or absence of previous treatment and semen findings (concentration, motility and morphology) were analyzed to determine parameters associated with the program. Results:  Patients in their 20s were most common (64 cases) and 94 cases were unmarried at the first visit. The main underlying diseases were testicular tumor (53 cases), leukemia (43 cases) and malignant lymphoma (13 cases). The program was completed for 118 cases. For leukemia, all semen parameters were closer to normal in patients without previous treatment (untreated group, UG) compared with the treated group (TG). When semen findings in the UG were classified according to underlying disease, sperm concentration was lower in patients with testicular tumor compared with those who had leukemia or malignant lymphoma. Four couples underwent reproductive therapies with the cryopreserved sperm through assisted reproductive technology, and three babies were born to two couples. Conclusion:  Sperm cryopreservation liberates patients with malignancy from iatrogenic infertility as a consequence of intensive therapy, allowing them to retain reproductive ability.