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This thesis describes a research of the behaviour of the elliptical CFT columns under axial loading. The most substantial part of this research is experimental works conducted on twenty-seven specimens including the hollow stub columns as references. Parameters such as slenderness ratio, uni-axial compressive strength of concrete infill and the aspect ratio were considered to investigate their influence on the behaviour on these columns. The results presented are the first member buckling tests on elliptical CFT columns. Keys results from the tests have been presented and discussed. Parallel with the experimental works, numerical analyses were carried out and verified with the experimental results. Parametric studies were performed following the validation of the numerical models. As there is no design guidance seems to be available in any standard, thus this research provides a review of the existing design standards of Eurocode 4 (EC4) and American Specifications (AISC). The design expressions from these current design provisions for circular, square and rectangular concrete- filled tubes design strengths were used to predict the capacities of elliptical eFT columns. The influences of concrete enhancement, steel reduction due to biaxial effects and column slenderness were all incorporated in design rules of EC4. Based on the experimental, numerical findings the evaluations were made on the design rules of the codes. This investigation was aimed at providing reliable design guidelines for practising engineers to employ the elliptical concrete-infill columns in the construction industry.