Many species of female moths produce sex pheromones to attract conspecific males. Most moth species utilize Type I pheromones that consist of straight-chain compounds 10-18 carbons in length with a functional group of a primary alcohol, aldehyde, or acetate ester, and usually with several double bonds. Studies over the past three decades have demonstrated that female moths usually produce sex pheromones as multi-component blends in which the ratio of the individual components is precisely controlled, making it possible to generate species-specific pheromone blends. As for the biosynthesis of Type I pheromones, it is well established that they are de novo synthesized in the pheromone gland (PG) through modifications of fatty acid biosynthetic pathways. However, because many of the molecular components within the PG cells (enzymes, proteins, and small regulatory molecules) had not been functionally characterized, the molecular mechanisms underlying sex pheromone production in PG cells remained poorly understood. To address this, we have characterized some of the key molecules involved in the biosynthesis of the sex pheromone bombykol in the silkmoth, Bombyx mori. Characterization of these molecules has facilitated our understanding of the precise mechanisms underlying lepidopteran sex pheromone production.