Aim Survival rates of childhood cancer are now above 80%, so there is increasing emphasis on survivorship. A major late effect of cancer treatment is fertility loss. International best practice indicates that post-pubertal boys with cancer should be offered sperm cryopreservation prior to treatment. The aim of this study was to demonstrate the feasibility of a national sperm cryopreservation program for adolescent males and to examine outcomes for a pilot. Methods Patient demographics and semen parameters of adolescent male oncology patients referred to our service were analysed. Sperm analyses were performed in accordance with WHO guidelines. Results Fifteen patients were referred, 12 of whom (80%) attempted sperm production. Of these 12 samples, 25% (3/12) were unsuitable for freezing. One patient was too unwell to produce a sample. Eight patients (age range 12-17 years) had sperm successfully cryopreserved. Of these 8 samples, 25% were within WHO 'normal' limits, 50% had reduced sperm concentration. The number of cryopreserved samples (straws) ranged from 4-8 per patient. Conclusion We have established a successful, structured fertility preservation service for adolescent males in Ireland. Sperm cryopreservation is an accessible method of safeguarding fertility in male patients facing cancer treatment and should be offered to all.