An injection moulding study that utilised an L9 (34) Taguchi array to determine the optimal process condition of a semi-crystalline PP grade is discussed. This used a multipurpose tensile bar geometry with the objective to maximise the mechanical properties, i.e. tensile modulus and strength (ISO 527), flexural modulus (ISO 178) and Izod impact strength (ISO 180, unnotched). After determining the optimal process settings, analysis of variance (ANOVA) revealed that packing time (among injection time, melt temperature and packing pressure) was the most dominant process factor for all the measured mechanical properties.