Tyrosine transport was examined in cultured skin fibroblasts from patients with schizophrenia (DSM-III-R) and normal subjects. The transport capacity (Vmax) was lower in the patients. The results confirm previous findings of decreased tyrosine transport in schizophrenia. In cells incubated with psychotropic drugs at different concentrations, tyrosine transport was not differentially influenced across patients and normal subjects. Dopaminergic and beta-adrenergic receptor mechanisms did not seem to influence tyrosine uptake. There seems to be a primary disturbance of tyrosine transport in schizophrenia which indicates a generalized cell membrane dysfunction.