• A brief psychometric battery was used to differentiate a sample of 56 individuals classified as having mild senile dementia of the Alzheimer type (SDAT) from 38 individuals with moderate SDAT. Using discriminant analysis techniques, a modest differentiation was obtained. It was noted that specific ability domains, namely, short-term recognition memory, visuospatial reasoning, and verbal ability, contributed to the discriminant function. Although the same domains have been found to differentiate SDAT at earlier stages, individual tests varied in the current sample as a function of marked decrements in ability levels at this advanced stage of the disease. The results suggest that the effectiveness of specific psychometrics for differentiating individuals with SDAT may vary as a function of relative disease stage.