Background & Aim: One of the most important and useful models for assessing hospital performance is the Pabon Lasso Model, a graphical model that determines the relative performance of hospitals using three indicators: 1. Bed Occupancy Rate (BOR); 2. Bed turnover (BTO); 3 Average Length of Stay (ALS). The aim of this research is to investigate the performance of the hospitals affiliated with Tehran University of Medical Sciences in Iran during the year 2011 based on the Pabon Lasso Model.

Materials & Methods: This descriptive and cross-sectional study conducted in 2011.  All the 16 hospitals affiliated to Tehran University of Medical Sciences formed the study population. Data was analyzed by Excel software and Pabon lasso model.

Results: The following average results for each performance indicator were obtained: Average Length of Stay (ALS) = 6.55 days. Bed Occupancy Rate (BOR) = 74.151% and Bed Turnover (BTO) = 70.24 times per year18.75% hospitals were located in the Pabon Lasso Model zone 1.25% hospitals in zone 2.25% of hospitals in zone 3, and 31.25% hospitals in zone 4 of the model.

Conclusion: The study showed that 75% of the studied hospitals were inefficient. Applying Pabon Lasso model compared hospital's performance. Thus, using one of the active ways of problem recognition in hospitals and perceiving the relation of performance indicators will be helpful in establishing new policy and reviewing current policy in order to maximize performance capacity.