Data were obtained on offenders, victims, and offense circumstances and on first instance and appeal outcomes. The total data set included 256 offenders, 239 victims, and 225 offenses. Offenders were separated by defense type--diminished responsibility, provocation, diminished responsibility and provocation, and other. Half of offenders were sentenced for murder and half were sentenced for manslaughter. The defense of diminished responsibility was argued more often than the defense of provocation. The acceptance rate for diminished responsibility, however, was lower than the acceptance rate for provocation, while the combination defense of diminished responsibility and provocation had the highest acceptance rate. Male offenders vastly outnumbered female offenders. Females were more likely than males to have either the partial defense or the combination defense accepted. Sentences for diminished responsibility cases fell at the upper end of the sentencing range for manslaughter. Juries rejected the defense of diminished responsibility in over half of cases where that defense was argued. Female offenders who established diminished responsibility were all diagnosed as suffering from either major or severe depression. The defense of diminished responsibility appeared to arise from a very small set of diagnostic conditions. 3 tables