In this paper the performance of an ejector refrigeration cycle was investigated theoretically and experimentally. Making use of the conservation of mass and energy as well as the exergy balance equations, a two-dimensional thermodynamic model was developed. The influence of flow viscosity is taken into account through considering a two-dimensional flow near the ejector inner wall. The results indicate a decrease of COP with increasing generator temperature and an increase of second law efficiency with increasing evaporator temperature and/or decreasing generator temperature. It is found that at any generator temperature, there exist a particular evaporator temperature above which the exergy destruction in the condenser is higher than that in the ejector. The maximum relative and the root mean square errors in calculating the entrainment ratio at three generator temperatures of 77, 83 90 o C are obtained as 7.76% and 5.13% respectively. Also the exergy destruction in the evaporator at an evaporator temperature of 13.5 oC, was found to be the highest among those occur in the other components of the cycle.