In this study, gas atomization parameters for aluminium powder production have been investigated. Experiments have been carried out at the Gazi Gas Atomization Unit. In the experiments Mannesmann type gas nozzles have been used and molten metal has been flowed freely. The pressures of air and nitrogen gas used during the atomization have been changed between 1.0 MPa and 4.0 MPa. Molten metal flow rate, exit area and angle of the gas from the nozzle and nozzle gas circulation diameter have been controlled during the experiments. Thus, effects of gas type, gas pressure and nozzle geometry on powder size have been examined. Dimensional analysis of produced powders have been made with the Malvern Mastersizer E laser micro powder size measuring instrument.