Flow properties of metal composite suspensions have significant impact on the fibre orientation during mould filling. Flow properties are strongly influenced by fillers concentration. The results presented in this paper relate to the flow properties of a composite suspension of aluminium powder and glass fibres compounded into a sacrificial polymeric binder. A range of aluminium mixes and composites were investigated over a wide shear rate range experienced during the Injection Moulding process. Aluminium composite suspensions were prepared by replacing glass fibres for aluminium powder. An optimum level of fibre content without deteriorating viscosity of the mix is determined. The effect of moulding temperature on the flow behaviour of aluminium composite mixes was also investigated. © 2004 Woodhead Publishing Limited. All rights reserved.