OBJECTIVE To study rate of progression and correlates of cognitive and functional/behavioral deterioration in Alzheimer patients. DESIGN A 1-year multicenter prospective study. SETTING Outpatients and inpatients at geriatric institutions. PATIENTS Fifty-six patients with a clinical diagnosis of Alzheimer's disease according to DSM-III criteria of Primary Degenerative Dementia. MAIN OUTCOME MEASURES Blessed Dementia Scale (BDS) and Blessed Information-Memory-Concentration test (BIMC) measured at baseline, third, sixth, and twelfth month. RESULTS The mean annual (+/- SD) rate of progression of our sample was 3.5 (+/- 3.7) points on the BDS and 2.6 (+/- 4.9) on the BIMC, with a wide range of variability. The level of cognitive impairment (BIMC score) at baseline predicted functional and behavioral deterioration: the better the initial BIMC score, the less the rate of negative change of BDS (r = 0.37, P = 0.006). Furthermore, the younger the patients at the disease onset, the faster the progression of cognitive impairment (r = 0.48, P = 0.0003), with men having a slower rate of progression (P = 0.004) than women. CONCLUSIONS The present study confirms previous findings showing a wide individual variability in rate of progression of cognitive and functional/behavioral impairment as assessed by BIMC and BDS. The cognitive profile may predict the clinical evolution better than the functional and behavioral status, with patients with an earlier onset and women having a faster deterioration.