After distinguishing between mental illness and mental retardation, this article discusses judicial, constitutional, and dispositional issues in the sentencing of mentally retarded (MR) offenders. The discussion covers competency tests and the fundamental rights of MR defendants. A review of the disposition of the MR offender addresses individualized sentencing, probation, incarceration, capital sentencing, the special-commitment process, diminished-capacity diversion, and habilitation. The article concludes that the relevant American Bar Association Standards are a useful guide for the judge in sentencing an MR offender. By focusing on the offender's intellectual functioning and maladaptive behavior, the standards justify the individualized sentencing decisions which must be afforded MR offenders. The standards also provide for alternative placement when the prison setting is deemed inappropriate for MR offenders. The standards emphasize the importance of capable counsel and allude to the provision of postgraduate legal education programs in the area of mental retardation. 225 footnotes.