We evaluated with the Data Envelopment Analysis (DEA) 13 decision making units (DMU) at IDI -IRCCS for the years 2000 and 2001. Input variables were cost for medical personnel, cost for non medical personnel and number of beds; output variables was the number of discharged patients weighted with DRG. Later in a second model we delete the cases considered to be at high risk to be inappropriate for treatment as inpatients. DEA instrument is confirmed useful in the efficiency evaluation for DMU at hospital level, ranking were different between the two models. The Health Direction can utilise the analysis to understand reasons of inefficiency and for incentive policy.