Astaxanthin is a carotenoid reddish-orange pigment with remarkable biological activities and benefits in human health. It also provides enormous commercial value in the application of functional food, aquaculture, and pharmaceutical business. Presently commercial production of astaxanthin includes chemical synthesis, extraction, and isolation from natural microbial sources such as bacteria Agrobacterium aurantiacum and Paracoccus carotinifaciens, green microalgae Haematococcus pluvialis, and yeast Phaffia rhodozyma. Microbial production of astaxanthin by metabolic engineered microorganisms has developed for decades and become the main alternative in industrial astaxanthin production. Because of the increasing demand and importance of astaxanthin, biotechnological astaxanthin production has been established, and its biosynthetic pathway also has been studied in the heterobasidiomycetous yeast Xanthophyllomyces dendrorhous, green microalgae Haematococcus pluvialis, and the teleomorphic state of Phaffia rhodozyma. The introduction of biosynthetic astaxanthin pathway into Corynebacterium glutamicum, Escherichia coli, and Saccharomyces cerevisiae is also used in heterologous productions of astaxanthin. This chapter will discuss biosynthetic pathways and regulation of astaxanthin, astaxanthin production in natural sources and biotechnical methods, and the influence of environmental factors in astaxanthin biosynthesis. At the end of the chapter, perspectives concerning the innovative strategies for further developing astaxanthin production and its trends to improve the metabolically engineering microorganisms will be discussed.