The multi-axial yield behaviour of the aluminium alloy foam Alulight has been measured. Triaxial tests have been performed on a range of relative densities in order to compare the hydrostatic stress versus strain response with the uniaxial compressive response, and to probe the yield surface after prior hydrostatic compression. It is found that the degree of strain hardening in hydrostatic compression exceeds that for uniaxial compression, and the yield surface remains almost self-similar in shape after hydrostatic compaction. The measured yield surface provides support for the phenomenological yield model of Deshpande and Fleck (V. S. Deshpande, N. A. Fleck, Journal of Mechanics and Physics of Solids, 48, (2000), 1253). Upon reviewing the available experimental evidence from this and previous studies it is found that a broad correlation emerges between the relative density and the shape of the yield surface for metallic foams. (c) 2005 Springer Science + Business Media, Inc.