This paper reports the results of an experimental investigation on the behaviour of square High Strength Concrete (HSC) columns reinforced longitudinally with either steel bars or Steel Equal Angle (SEA) sections under concentric axial compression. The use of SEA sections as longitudinal reinforcement may enhance the load carrying capacity and ductility of concrete columns. These enhancements are because for a given cross-sectional area, a SEA section has a higher second moment of area and radius gyration than a steel bar. Also, the SEA sections provide a greater confinement area for the concrete core of columns. A total of 6 column specimens with a square cross section of 210 mm and 600 mm height were tested under concentric axial compression. The specimens were divided into two groups and each group contains three specimens. The specimens in the first group (Group 1) were reinforced longitudinally with four N12 (12 mm diameter) deformed steel bars and served as reference specimens. The remaining four specimens in the second group (Group 2) were reinforced longitudinally with four A30 (29.1 mm x 29.1 mm x 2.25 mm) SEA sections. The lateral reinforcement spacing in each group of specimens varied between 50 mm and 200 mm. The influence of the type of longitudinal reinforcement (steel bars and SEA sections) and the spacing of the lateral reinforcement on the performance of the column specimens were investigated and discussed. The results of this investigation showed that for specimens reinforced with SEA sections, the ductility significantly enhanced compared to corresponding specimens reinforced with steel bars. The test results also indicated that as the lateral reinforcement increased from 50 mm to 200 mm, specimens reinforced with SEA sections showed better enhancement in ductility and strength than the specimens reinforced with steel bars.