Tissue distribution of Type V collagen in comparison with Type IV collagen was investigated by indirect immunofluorescence microscopy. Affinity-purified rat antibodies to Type IV and Type V collagens obtained from human placenta reacted specifically only with the corresponding type of collagen in both native and denatured conformations. In indirect immunofluorescent stainings of human skin, lung, and cornea tissues, Type IV and Type V collagens showed distinct distributions. Type IV collagen was distributed exclusively in basement membrane. However, Type V collagen had two characteristic features; a diffuse distribution in interstitium and the locations on or adjacent to basement membrane. On the basis of these findings and of biochemical characterization of the collagens, it is postulated that Type V collagen is an intermediate collagen, possibly having a function of binding or connecting of interstitial collagen fibrils with membranous collagen networks.