Beam with ideal support, ideal geometry and ideally loaded cannot be expected in real engineering applications. Imperfections, though small, may cause substantial deviation from the theory, which describes ideal beams. In this diploma thesis, we present experimental apparatus for testing effects of different support and load imperfections on the response of axially loaded beam. The problem is first approached analytically with the derivation of the deflection equation of initially curved beam according to the exact and linearized theories. We use our experimental apparatus and test the effect of initial curvature and eccentric application of the load. The results of the measurements at the test site are compared with the results of theoretical calculations.