Even when confronted with life-threatening illness, patients understandably place emphasis on fertility preservation. This is compounded with the fact that a substantial proportion of patients with certain malignancies, such as testicular cancer (TC), acute lymphoblastic leukemia (ALL), and Hodgkin's lymphoma (HL) have pretreatment reproductive potential. This chapter reviews the main effects of cancer treatment on fertility and presents the contemporary approach to fertility preservation. There are several mechanisms of treatment-induced fertility impairment. Several successful pregnancies after female and male use of second generation tyrosine kinase inhibitors have recently been reported; however, there is still limited experience with imatinib drugs. Fertility preservation is an integral component of contemporary treatment plans for patients with cancer. The chapter discusses the naturally methods of fertility preservation which differ between male and females. The probability of treatment-induced fertility impairment should be weighed up against the potential side effects and efficacy of fertility preservation.