Dehydrodolichyl diphosphate synthase (DHDDS) catalyzes cis-prenyl chain elongation to produce the polyprenyl backbone of Dolichol, a glycosyl carrier-lipid required for the co-translational modification of various proteins. The resulting glycoproteins play a role in several physiological and pathological processes. This manuscript characterizes the DHDDS-like gene from rainbow trout (Oncorhynchus mykiss) and its tissue-specific mRNA abundance in two different strains. The ubiquitous expression of DHDDS in trout indicates the essential function of the product Dolichol for metabolic processes. The comparison of the deduced amino acid sequence with DHDDS proteins from different vertebrate, invertebrate, and herbal species reveals a high degree of conserved amino acids and protein regions suggesting a common functional relevance. This is the first report of a prenyltransferase homologue from a teleostean species.