Abstract: An aluminum alloy composite sheet is described for use in brazing. It includes an aluminum alloy core sheet clad on at least one face thereof with a sheet of aluminum or aluminum alloys including those containing magnesium. The composite sheet is useful for brazing when the cladding is coated with a mixture of (i) metal particles, e.g. silicon, capable of forming a eutectic alloy with aluminum and (ii) brazing flux, e.g. a potassium fluoro-aluminate. To be effective for brazing, the magnesium must be present in such quantity that at the time of brazing, the surface being brazed contains less than 0.1% by weight magnesium.