In this paper we use Data Envelopment Analysis and the Malmquist Productivity Index and its decompositions to assess the productive efficiency and productivity of the in-patient clinics of a large Greek University General Hospital. Clinics are represented by means of a simple model whereby they use inputs (labor and capital) to produce outputs (in-patient days and patient discharges). The efficiency model is input oriented and assumes constant returns to scale. Model validation analyses showed that this model appears to be externally valid. The framework proposed here is a simple and useful tool for informing intra-hospital management decisions.