A many behavioral disturbances, Stereotypic behaviors are among the best discriminators of Frontotemporal Lobar Degeneration (FTLD). A recent preliminary report suggests many of the behavioral symptoms, including stereotypic behaviors in FTLD patients, respond to medication with selective serotonin re-uptake inhibitors. However, there is no scale that evaluates stereotypic behaviors comprehensively. To assess the wide range of stereotypic behaviors encountered in FTLD, we developed a new instrument, the Stereotypy Rating Inventory (SRI). The SRI assesses five distinctive stereotypic behavioral disturbances often seen in patients with FTLD: eating and cooking behaviors, roaming, speaking, movements, and daily rhythm. The SRI uses the same technique as the Neuropsychiatric Inventory (NPI) in that both the frequency and the severity of each behavior are determined. The studies reported here demonstrate the content and concurrent validity, as well as inter-rater and test-retest reliability, of the instrument. Scores of FTLD patients (n=26) on the SRI were much higher than those of patients with Alzheimer's disease (n=46), patients with vascular dementia (n=26), and normal control subjects (n=40). The SRI appears to be a useful instrument for detecting stereotypic behaviors and monitoring of therapies in FTLD patients.