Poultry is an integral part of animal agriculture, and they provide the human population with products such as meat and eggs. In poultry production, as with other livestock systems, a high level of reproductive performance is absolutely crucial to efficient production. In order to manage poultry reproduction and the specific problems that arise, it is important to understand the underlying physiology of the reproductive process. Thus, this book aims to provide an integrated overview of the subject of poultry reproduction, describing the normal function of the reproductive system. The book is designed to provide a general background to the field of poultry reproduction for postgraduate and undergraduate students, and a reference source for research scientists and professional workers in the field related to the production of animal products. The book will serve as an introductory text to veterinary students embarking on a career in reproductive physiology research. Furthermore, we hope that it will be used by working veterinarians and farmers to update themselves on new research findings and developments in the management of poultry reproduction. Since the mid the 19th century, several studies characterizing the anatomy and physiology of the male and female reproductive systems of poultry have been conducted. This book focuses mainly on the review of current literature on physiological mechanisms regulating reproduction with emphasis on poultry species. It describes the basic structures and functions of the male and female reproductive tracts including the sex organs (testis, ovary), excurrent ducts, accessory organs, oviducts, shell gland and vagina. The endocrine glands that control reproduction in poultry were also described. The process of sperm production and egg formation are discussed including highlights of the recent literature on factors that affect spermatozoa production and function. The basic fundamental structure and chemical characteristics of the eggs were defined. Key elements of the egg production are discussed including synthesis and transfer of egg yolk constituents, the formation of the egg yolk in the ovary, development of oocytes and ovulation, the formation of egg white and chalazae, the formation of eggshell and oviposition. This section also described in detail the sperm-egg binding, sperm acrosome reaction and protease enzymes required for the hole formation in the perivitelline membrane and the development of the diploid zygote emanated from the fusion of the nuclei from both male and female gametes. The editors have succeeded in bringing together many renowned poultry reproduction experts to review the current body of knowledge in poultry reproduction and are grateful to all the authors for their state of the art compilation of the most recent development in this field. We feel that we have achieved our goal of producing an outstanding book, with the top scientists in their field addressing each subtopic. I.P. OgbuewuI.C. OkoliM.U. Iloeje