BACKGROUND Sperm cryopreservation, an effective method for preserving male fertility, is very advantageous for men suffering from cancer. Unfortunately, as both physicians and cancer patients are unaware of the possibilities for sperm cryopreservation, the data on evaluation of semen parameters and disposition of cryopreserved samples among Chinese cancer patients are scarce. RESULTS Male tumours were classified into six major types, germ cell tumours (26 %), haematological neoplasms (28 %), head and neck cancers (19 %), thoracic tumours (4 %), abdominal tumours (10 %), and others (13 %). Haematological neoplasm was the most prevalent cancer among our cohort of patients who opted for sperm banking, followed by germ cell tumours. Patients with germ cell tumours had the lowest pre-thaw and post-thaw seminal sperm concentrations. We separately compared patients with testicular tumours, lymphoma, and leukaemia, and found that leukaemia patients had the lowest pre-thaw sperm concentrations. Most cancer patients (58 %) chose to keep their specimens stored, while 31 % chose to discard the specimens. Over the years, only 13 patients (4 %) returned to use their spermatozoa by assisted reproductive technology. Of the stored samples, patients with germ cell tumours constituted the highest proportion (29.3 %). Moreover, the percentage of haematological neoplasm patients who had no spermatozoa frozen was the highest (46.2 %). CONCLUSIONS The present data confirm the deleterious impact of various cancers on semen quality. Leukaemia was associated with the worst semen quality and the highest number of semen samples that could not be frozen. We suggest that sperm quality may have decreased even before anti-neoplastic treatment and that sperm banking before treatment should be strongly recommended for cancer patients. A sperm banking programme before gonadotoxic therapy requires close cooperation between assisted reproduction centres and cancer clinics.