This paper presents a nonlinear 3-D finite element model highlighting the structural performance and strength of built-up cold-formed steel section battened columns. The pin-ended columns were axially loaded and consisted of two cold-formed steel channels placed back-to-back at different center-to-center distances. The built-up columns had different geometries and different slenderness ratios. The nonlinear material properties of cold-formed steel, initial geometric imperfections and built-up section column components were considered in the finite element models. The finite element models were verified against tests conducted by the authors on the same form of construction. The column strengths, load-axial shortening, deformed shapes at failure, failure modes, load-lateral displacement and load-axial strain relationships were predicted from the finite element analysis and compared well against the test results. The verified finite element model was used to perform parametric studies investigating the effects of different parameters affecting the built-up column strength and behavior. The columns strengths predicted numerically were compared with design strengths calculated using current codes of practice. Based on the numerical results, new design rules were proposed for built-up cold-formed steel section (BCFS) battened columns.