Composite steel-concrete floors are wide ly used throughout the world for building applications. These floors usually consist of composite slabs supported by steel beams in steel framed construction and of post-tensioned composite slabs carried by band b eams in concrete buildings. The design of com posite floors is commonly governed by serviceability lim it state associated with deflection limits. Recent research has pointed out that a non-uniform shrinkage profile occurs in slabs cast on profiled steel sheeting. In this context, this paper provides a brief overview of the m ain factors influencing the service behavior of com posite slabs and of a model capable of predicting their long-term deflections considering two approaches for the evaluation of the non-uniform shrinkage profiles, i.e. a simplified approach and a hygro-therm o-chemical-mechanical model. The adequacy of the proposed prediction m odels is then outlined by comparing the longterm deflections calculated with the proposed approach and those m easured experimentally from long-term tests carried out on selected composite and post-tensioned composite slab samples that have been reported in the literature.