Besides morphological images created by optical coherence tomography (OCT), another inherent physical parameter is evaluated in skin tissue under in vivo conditions. Refractive indices may support tissue characterization for research and diagnostic purposes in cosmetics/pharmacy and medicine, respectively. To accomplish refractive index evaluation, the sample arm of our OCT setup has been arranged to minimize mechanical adjustment and yet accommodate a wide parameter range at the entire penetration depth of up to 1 mm. A simple algorithm for local mapping has been derived. Refractive index maps have been measured locally in skin of stratum corneum, epidermis and upper parts of the dermis. Dry and moist skin areas have been observed by refractive index evaluation.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.