Recent evidence indicates that developmental anomalies may underlie some symptoms of schizophrenia, while psychophysical studies have demonstrated olfactory deficits in this disease. The postmortem olfactory mucosa of elderly schizophrenic patients was examined to characterize the molecular phenotype of this tissue. The distribution of developmentally regulated cytoskeletal proteins, a synaptic vesicle protein, a neural marker protein, a receptor for trophic molecules, axonal guidance and cell migration proteins, and neuronal and glial cytoskeletal proteins of various degrees of phosphorylation was examined by immunohistochemistry. Both schizophrenic and control subjects exhibited dystrophic neurites that were immunoreactive for synaptophysin, microtubule-associated proteins (MAP1B), and neurofilament proteins. No major histochemical or morphologic differences in either the expression or distribution of these proteins were observed in the olfactory epithelium of schizophrenic compared to control subjects. These studies indicated that dystrophic neurites frequently occurred in the olfactory mucosa of both schizophrenics and neurologically normal adults. The absence of major immunocytochemical abnormalities suggested that olfactory deficits in schizophrenia may be due to more subtle cellular or molecular differences or to abnormalities in olfactory regions of the central nervous system rather than in the olfactory epithelium.