ELOVL4, elongation factor of very long chain fatty acids-4, is known to be responsible for autosomal dominant macular degeneration and Stargardt-like macular degeneration. In this study, we cloned the monkey homologue of ELOVL4 and determined the cellular and tissue distribution of the gene product. Sequence analysis of the monkey ELOVL4 gene revealed a high degree of homology between human and monkey. The cloned full-length cDNA of monkey ELOVL4 encoded 314 amino acids, the same length as human and two amino acids longer than mouse. The monkey ELOVL4 conserved the characteristics typical of the super family of ELO enzymes involved in the metabolism of membrane-bound fatty acid elongation. Real-time quantitative PCR demonstrated that the monkey ELOVL4 gene was highly expressed in restricted tissue-specific fashion, not only in the retina but also in the skin (90% of retina) and thymus (111% of retina). Immunohistochemical analysis detected signals predominantly in the photoreceptor layer of the monkey retina.