This study presents experimental and numerical testing of the steam condensing flow through a linear blade cascade made of blades of a 200 MW steam turbine last stage stator. The tests were carried out on an in-house laboratory stand and using an in-house numerical code modelling the water vapour flow with homo- and heterogeneous condensation. Additionally, this paper presents a comparison of calculations of a flow field modelled by means of a single-fluid model using both an in-house computational fluid dynamics code and the commercial Ansys CFX v16.2 software package. The aim of the research was to identify difficulties involved by comparing the numerical modelling results with the experimental data for a linear blade cascade. The experimental results, which are very well supplemented by those obtained from numerical computations, may be used to validate computational fluid dynamics codes.