For the past 50 years, Australian composite slab construction has been at the forefront of technology. The major developments that have occurred over this period in this important form of construction are described. It began with the novel adoption of high-tensile galvanised steel to form the steel deck, which had over twice the yield stress of mild steel. This same high-tensile steel is used today in every Australian steel deck, including the world’s longest-spanning commercial steel deck comprising a hybrid box-section, with unpropped spans up to 8.5 metres. Unlike when it was originally used, due to a number of major developments including a small-scale bond test, the steel in modern-day Australian decks generally bonds well enough in concrete to utilise most or all of its tensile strength, acting as main reinforcement in a composite slab. Anchoring the high-tensile base sheet of the hybrid box-section is particularly effective, giving it design advantages where concentrated loads are located on a slab, for example. A much more recent development (involving the formwork stage) has been to pre-camber the steel panels, avoiding temporary propping and achieving a flat composite slab soffit without detrimental concrete ponding effects. Astute builders and designers recognise the overall commercial benefits that arise from these advances. Other developments allow the accommodation of two-way reinforcement arrangements, vertical and horizontal building services, and voids to reduce concrete volume and weight and correspondingly the size of permanent supports. Background research and detailed case studies are described regarding the range of Australian steel decks.