Historically, the deaf-mute (prelingually deaf) defendant has been viewed much as a mentally disordered defendant, as the deaf-mute was presumed to lack criminal responsibility in early common law. Legal commentators have recently suggested that prelingually deaf offenders may have impaired competency as the subjects of police questioning, since they are incapable of understanding the Miranda warning. A population-based study of prelingually deaf defendants admitted to a maximum security psychiatric facility from 1971 through 1980 examined their prevalence and treatment. Prelingually deaf persons were disproportionately present in the hospital population compared to their number in the general population. This reflects the fact that the leading causes of prelingual deafness are also among the leading causes of neurologic damage and mental retardation. Although no definitive research has yet been done, the available evidence indicates that prelingual deafness per se does not contribute substantially to criminality and delinquency. Any claim of association between deafness and criminality must give account to the possibility that deafness decreases the probability of evading apprehension and to the fact that prelingual deafness is associated with other factors related to criminality, such as impaired brain functioning, education underachievement, social isolation, and unemployment. 62 references and 1 table.