Mithun (Bos frontalis), the unique bioresources of North-eastern hilly states of India, is currently reared under ‘free-range conditions in shrubby hill forests at altitudes ranging from 1,000 to 3,000 m above mean sea level. With the decreasing forest coverage in the region, it has become imperative to adopt a semi-intensive or intensive rearing system in near future. This warrants the need for the preservation of elite mithun germplasm and the adoption of artificial insemination. Semen cryopreservation and artificial insemination (AI) have revolutionized the animal breeding industry. However, the scientific information on mithun reproduction including semen cryopreservation and artificial insemination is scanty. This book describes the selection of breeding bulls, sexual behavior, semen collection, and evaluation techniques, the process of cryopreservation, and artificial insemination in mithun. In addition, this book also deals with the endocrinological profiles including the effect of season and melatonin on seminal profiles. For easy understanding, the information is presented with adequate pictorial and graphical representations. This book will be helpful for the breeders, veterinary professionals, and students in understanding of different aspects of reproduction in mithun bull and preservation of mithun germplasm. The semen cryopreservation techniques described in the book will not only help in taking up future programs of genetic improvement and conservation of mithun but will also pave the way for adopting assisted reproductive technologies.