We have established 44 Schwann cell cultures from human peripheral nerves that underwent biopsy for diagnostic purposes using a new "sandwich" connective tissue and cut into 1 mm cubic explants which were placed between two glass coverslips coated with D-poly-L-lysine, in HAM-F10 medium, 15% FCS, 600 mg/dl glucose and antibiotics. In the first 3 weeks this new sandwich technique yields a fairly great and homogeneous amount of Schwann cell growth, with only a few fibroblasts and virtually no macrophages and provides a suitable substrate on which immuno cytochemical studies could be performed.