The paper presents the results of simulations of deterministic size effect in concrete bars and beams. Two established material models are employed in the study: the consistency viscoplasticity and the gradient damage model. For direct tension of a double-edge notched bar three sizes are considered. For three-point bending of a beam without a notch four sizes are examined and the response is compared with experimental results taken from a paper by Grégoire et al. The results confirm that the regularized models exhibit size effect not only in the post-peak regime, but also in the nominal strength. It is more pronounced for the gradient damage model.