A Taguchi design investigation has been made into the relationship between the microporosity and process variables in a sand cast A360 aluminium alloy. The effects of various casting parameters including mold filling, liquid filtering, solidification time, the dissolved hydrogen level of the liquid alloy and liquid treatments of molten alloy with Sr addition were investigated. Results showed that within these five casting parameters investigated, the local solidification time and the dissolved hydrogen level of the melt were significant on the microporosity. Accordingly, the other casting parameters have been found to be less influential on the final pore size and their distribution. (c) 2006 Elsevier Ltd. All rights reserved.