High-strength concrete (HSC) is common.ly used for columns that need to withstand significant compressive forces and bending moments. However, the brittleness that characterized HSC behaviour negatively affects the ultimate strength and ductility of columns. Thanks to fibres, high-strength fibre:-reinforced concrete (HSFRC) and ultra-highperformance fibre-reinforced concrete (UHPFRC) have a rather ductile behaviour in tension and compression and may be used to improve the structural response of highly stressed columns, thus leading to thinner sections and a reduction of ordinary reinforcement. This paper presents the results of a preliminary test campaign on HSFRC and UHPFRC columns under bending with normal force. Several atrrangements of ordinary reinforcement were tested, including columns without any longitudinal or transversal reinforcement. The observed behaviour is interpreted by means of a miechanical model. Based on test results and parametrical analysis, the contribution of fibre:s to the structural response and the possibility to replace ordinary reinforcement with fibres are discussed.