Fertility preservation is feasible in the majority of men. Herein, we review the reproductive toxicities of commonly encountered clinical threats to male fertility, including cancer, radiotherapy, chemotherapy, surgery, and nonmalignant diseases treated with immunosuppression. Other scenarios, in which fertility preservation may be considered, such as Klinefelter syndrome, acute testicular injury, and sudden unexpected death, are also discussed. We provide an algorithmic approach to fertility preservation in men, and review strategies for sperm acquisition in cases of ejaculatory dysfunction and azoospermia. Lastly, emerging options for fertility preservation in prepubertal boys are discussed.