Silk is the queen of textiles. The Asian region supplies silk to the world market. China accounts for the bulk of silk exports to the world. Japan realized the importance of silkworm breeding and contributed a lot to the development of sericulture. However, till recently this development of technology was not given out and was kept as a secret. The language also acted as a barrier in this respect. The breeding techniques developed by Japanese were for temperate regions. At present due to electronic revolution the silk producing countries of the Asian region are experiencing changes in their production patterns. Advanced sericulture countries like Japan and Korea are showing some decline in their silk output levels. Other developing countries like India, Bangladesh, and Sri Lanka etc. that belong to the tropical belt have realized the potential benefits, such as alleviating rural poverty through employment and income generating activities.The main aim of writing this book is to make basic techniques of silkworm breeding more comprehensive it includes fundamental principles which are most common and directly applicable to breeders. The basic techniques are emphasized to stress practical applications in order to achieve breeding aims under various environmental conditions.The data given in the text is mostly for bivoltine breeds. This publication, therefore, intends to serve as a hint book for researchers who are planning to organize or initiate a breeding plan in silkworm breeding.The purpose of silkworm breeding is to improve economic characters. The breeding and popularization of good varieties of silkworms not only enhances farmer's income, but also improves cocoon qualities and reeling process. The silkworm cocoon and raw silk production is primarily based on successful breeding of good silkworm varieties. The improvement of silkworm varieties for higher cocoon yields is an efficient way to achieve good quality raw silk. The breeders have to aim at improving the overall productivity of silk per unit area of mulberry plantation. Besides this, the breeders in India shall have to address themselves about the real problems prevailing in India viz., high temperature in tropics, poor quality mulberry leaves, and heavy pathogen load in the micro environment.So far, the critical information in developing superior silkworm breeds of commercial interest has remained confined to Seri culturally advanced countries. As such there is a need to assist developing silk producing countries to improve breeding capabilities, and breeding techniques. The information and literature on silkworm breeding is not very much available, hence an attempt has been made to compile and to share the views. The book gives a general introduction to breeding with special reference to silkworm breeding. I hope the information contained will be useful to the silkworm breeders. The book is expected to fill the void being felt in the field of sericulture and especially in silkworm breading to evolve new breeds. Further the sericulture being introduced in graduate and post graduate levels in different states of the country the book is expected to be of immense help to the student's community in particular and the associated scientific fraternity in general.