Six hundred and sixty nine out patients with mild to moderate Alzheimer's disease were enrolled by 193 French neurologists, psychiatrists and gerontologists. The patients, 38p.cent males and 62p.cent females with a mean age of 75 years were progressively titrated from 3 to 12mg by day of rivastigmine, Exelon((R)), a day, and treated for 6 months. Mean Mini-Mental State (MMS) at baseline was 18.6. Concomitant pathologies and treatments were present in 89p.cent of the patients. Safety was good though 86p.cent reported an adverse event which was mild in most of the cases. The premature drop out rate was 29p.cent. Seventy-five patients showed no change or an improvement in their 4 Instrumental Activities of Daily Living (IADL) score with no change in the MMS at the end of treatment (18.8). Four items of the Neuro-Psychiatric Inventory (NPI): delusions, anxiety, apathy, and irritability were significantly improved at week 12 and the improvement in anxiety was still significant at the end of treatment. The total score frequency X severity showed a tendency to improvement. The correlations between the sum of the 4 IADL, MMS and NPI scores were strongly significant.