We have cloned and sequenced the red opsin gene, rCh, of goat (Capra hircus). When rCh is expressed in cultured cells and reconstituted with 11-cis retinal, the resulting visual pigment has a wavelength of maximal absorption (lambda max) of 553 nm. This result and the deduced aa sequence of the goat red opsin suggest that the lambda max values of the red pigments of goat and human are based mainly on Y277 and T285. The slightly lower lambda max value of the red pigment in goat than in human (approximately 560 nm) can be explained by a single aa difference between the goat (A180) and human (S180) red pigments.