This paper is concerned with the time-dependent buckling behaviour of continuous composite steelconcrete T-section beams with varying degree of shear connection. Creep and shrinkage effects in composite steel-concrete structures may cause a redistribution of internal actions within a member, which increases significantly the compression within the steel component, and that may lead to erosion of the buckling resistance of the steel member. In this paper, models for the in-plane analysis of continuous composite beams with varying degree of shear connection stiffness and subjected to creep and shrinkage of the slab, and the out-of-plane buckling analysis capable of predicting local, distortional and lateral buckling modes are combined to study the time-dependent buckling behaviour of continuous composite beams. A parametric study is then undertaken to evaluate the effects of shear connection stiffness and geometric beam properties on the long-term elastic buckling capacities of these beams, and some conclusions are drawn.  Paper presented at the Fifth International Conference on Advances in Steel Structures, 5-7 December, 2007, Singapore