Abstract Experimental investigations on concrete indicate that for the same specimen geometry, the nominal strength of the specimen decreases with increasing specimen size. This phenomenon is called the size effect in fracture mechanics of concrete/reinforced concrete. In the present study, five series of push-off specimens of four different sizes but geometrically similar were tested in order to investigate the role of the size effect on dowel action and on to the bearing capacity of cracked reinforced concrete members. The maximum loads obtained from the test results were analysed by Bazant’s size effect law and the results were compared with the test data existing in the literature. In conclusion, the observed size effect is sizable and in good agreement with the size effect law.