ABSTRACT Monoclonal antibodies were raised against differentiated cells, and blastemal cells from regenerating limbs of adult newts (Notophthalmus viridescens) and screened for specific staining by immunocytochemistry. In addition to antibodies that identify muscle, Schwann cells and cartilage, two reagents were specific for subpopulations of blastemal cells. One of these latter antibodies, termed 22/18, has provided new evidence about the origin of blastemal cells from Schwann cells and myofibres, and also identifies blastemal cells whose division is persistently dependent on the nerve supply.