Rack columns are generally made of thin-walled steel sheets, and the steel sheets are cold-formed into the desired cross-sections. The columns are utilised to form upright frames of a storage system and serve as compression members. Currently, the theoretical and experimental investigations of the buckling behaviour of ?-shaped rack columns with patterned holes are rare, and the analytical design solutions for predicting the compression capacity of these columns are not mature yet. This paper presents a theoretical study of the elastic buckling behaviour of rack columns under uniaxial compression, and three different ?-shaped cross-sections were investigated. The columns without holes are studied first; then, patterned holes are considered for the columns. Buckling curves and signature curves of the columns are generated by using a finite element software, ANSYS 18.1, and two different boundary conditions, i.e., simple-simple and clamp-clamp are considered. The buckling curves of the rack columns with holes, under the boundary condition of pinned-pinned, are generated as well.  Three problems are mainly addressed here: (1) how to generate the signature curve of rack columns (without holes) by using conventional finite element programs (e.g., ANSYS); (2) what are the differences between the buckling behaviour of the columns with and without holes; (3) how to determine the critical buckling loads and critical buckling half-wavelengths of rack columns with holes accurately.