BACKGROUND: Sperm cryopreservation (freezing) should be offered to all men with cancer due to risk of infertility. However, many men with cancer already have impaired spermatogenesis prior to sperm cryopreservation. Furthermore, physical ill-health may hinder attendance of freeze visits. Investigating both the distribution of sperm functions and freeze attendance rates in men with newly diagnosed cancer, may identify patients benefiting from targeted reproductive fertility support. METHODS: We performed a retrospective study of 2906 male patients undergoing sperm cryopreservation prior to cancer therapy at a single UK tertiary centre between 1989 and 2013; all patients were asked to attend three hospital semen collection visits prior to cancer therapy. RESULTS: Fifteen per cent (433/2906) of men with newly diagnosed cancer had severely impaired semen quality (i.e., sperm total motile count, TMC < 1 million) during the first semen collection visit. However, patients with severely impaired semen quality had the poorest attendance of subsequent semen collection visits despite being requested to do so (non-attendance in TMC < 1 million: 43.4%; TMC < 1-30 million: 35.7%, P < 0.05 vs. <1 million; TMC > 30 million: 33.2%, P < 0.01 vs. <1 million). CONCLUSIONS: This study expands understanding of the semen quality of men with newly diagnosed cancer, and their ability to adhere to fertility preservation recommendations. Our data suggest that patients with the poorest semen quality paradoxically suffer the poorest attendance rates of sperm cryopreservation appointments prior to commencing cancer therapy. We suggest that additional support may be of clinical benefit to men with newly diagnosed cancer and TMC < 1 million sperm.