A method of producing reinforced metal matrix composite materials involves encapsulating the reinforcing components in metal foil and melting the resulting capsule in the matrix metal melt so that the latter infiltrates the reinforcing components. Preferably, the metal foil has the same basic components as the matrix metal melt or consists of a different material which alloys with the melt and infiltration may be carried out by pressure casting or other casting process. ADVANTAGE - The method is simpler, quicker and less expensive than conventional processes and requires no introduction of binder or other phases apart from the desired reinforcing phases.