The change of world climate and its attendant effect on scarce water resources have further reduced the availability of water for agriculture. Under this circumstance, the use of pressurized irrigation systems can be an option of enhancing the efficiency of water consumption. This study was therefore conducted to evaluate the performance of mini-sprinkler irrigation system and to determine optimum operating conditions that achieve high coefficient of uniformity (CU). An experiment was conducted on the experimental farm of faculty of Agricultural, Suez Canal Univ. Egypt. Four different commercially available makes of mini-sprinklers MSP1, MSP2, MSP3 and MSP4 of different nozzle sizes 0.85, 1.35, 1.5 and 2.0 mm, respectively were tested at 75 cm stake height for their hydraulic performance in terms of pressure-discharge, pressure-wetting diameter and pressure-average precipitation rate of single mini-sprinkler head relationships. The experiment was conducted at six different operating pressures of 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 bar. Polynomial equation of the form Q = aP2 + bP + C were developed for all types of four mini-sprinklers to describe the pressure-discharge relationship. On the basis of this relationship MSP4 was found to be superior over other three nozzles. Pressure- wetting diameter relationships was very well established by polynomial type equation of the form WD = aP2 + bP + C and MSP4 was to be superior over other three nozzles. Average precipitation rate was found to be decreases with increase in operating pressure. For all tested operating pressures and nozzle size, the CU increased with increased operating pressure until its maximum at 2.0 bar.