In this paper the local and distortional buckling analyses of axially loaded cold-rolled channel and sigma profiles were performed. The critical buckling load was computed by solving the linear eigenvalue problem for different numerical models using Finite Element Method and simplified formulas implemented in Eurocode and proposed by Hancock and Schafer. The buckling analyses were conducted to prove that the sigma cross-section can be successfully replaced by channel cross-section with additional elastic supports placed in folds of the web. It was demonstrated that the folds in the web of the sigma cross-section (additional elastic supports) reduce the slenderness of the web. So, the critical distortional stress can be calculated based on analytical formulas derived for the channel cross-section taking into account the web height between the folds.