This paper presents a detailed analysis of the influence of boundary conditions and axial deformation on the critical buckling loads of the geometrically perfect elastic two-layer composite columns with interlayer slip between the layers. An investigation is based on the extension of our preliminary analytical study of slip-buckling behavior of two-layer composite columns. It is proved that the boundary conditions of composite columns with interlayer slip are interrelated in longitudinal and transverse directions. The parametric analysis reveals that the influence of different longitudinal boundary conditions on critical buckling load is significant and can be up to 20%, while, on the other hand, the influence of axial deformation is negligible. (C) 2010 Elsevier Ltd. All rights reserved.