Glucocorticoid-resistant variants of L cells were characterized by somatic cell hybridization. Neither of the variants had a clearly dominant phenotype in hybrids with a glucocorticoid-sensitive fibroblast line. Hybrids of one of the resistant variants and a resistant fibroblast line showed complementation — the hybrid clones were sensitive to dexamethasone. Complementation, however, disappeared after continued culture of the hybrid cell