This evaluative review covers the neurotoxic effects of toluene. General health effects of toluene are also discussed in more limited detail. A brief description of chemical properties and environmental prevalence is given, followed by a review of pharmacokinetic data. General health effects include lethality, growth, morbidity, mortality, liver and kidney damage and miscellaneous effects. Neurobehavioral effects include epidemiological and clinical findings, activity and sleep, performance and learning, electrophysiological and central-nervous-system (CNS) effects. Evaluation and synthesis of data is included. It was concluded that low level exposure to toluene has its primary effect on the CNS. From a systematic or general point of view it is not clear what this effect is. Both depressant and excitatory effects (possibly concentration dependent) were reported as well as other kinds of results. Other health effects were not life threatening at any exposure level short of that producing lethality. Effects were reversible even at extremely high exposure levels for very long durations. Problems in research and needed data are pointed out. Given the economic importance and ubiquity of toluene, more information about its behavioral and neurological effects is sorely needed.