Poly(borazinylamine) has been investigated as a binder and as an in situ source material for boron and nitrogen in the frabrication of low volume fraction metal–matrix composites. The representative matrix metals employed in this investigation were aluminium, copper, iron, titanium, nickel and tungsten. The resulting metal–matrix composites contained metal borides and metal nitrides as the ceramic phases in 10.0 mol%, with the exception of copper which does not react with poly(borazinylamine). Although, the composites were prepared at ambient pressure, the aluminium- and titanium-based composites attained close to theoretical densities. The surface analysis of the composites by SEM and XPS showed the presence of a protective oxide layer composed of metal oxide and refractories.