The procedure of immunofluorescence localization of collagen types and laminin in frozen cut sections from oral mucosa is described. Tissue specimens may be obtained by surgery or from biopsy; fixation is optinonal, f.e. by aldehydes. Specimens are placed on a piece of aluminium foil (or in a special cryomold), covered by a drop of water soluble embedding medium such as Tissue-Tek®) and immediately frozen in liquid nitrogen cooled isopentane; frozen tissue blocks are tranferred to the cryo-chamber for sectioning. Frozen cut sections of 4-8 µm thickness are prepared with a cryo-microtome at -25°C to -30°C and using an anti-roll plate. For improved adherence of tissue sections, glass slides have been coated with special adhesives. The indirect immunofluorescence principle was applied: incubation in unlabeled primary antibody is followed by incubation in fluorescein (FITC) labeled secondary antibodies.