A novel approach to calculate the creep deflection of cracked flexural reinforced concrete members is presented. In contrast to existing methods, a rational mathematical model has been developed relating the creep factor established from prism tests to an equivalent creep factor pertaining to the flexural member. The predicions of this calculation method are compared with the results of four reinforced concrete beams tested for this purpose and other experimental work reported in the literature. The proposed method is shown to be in good agreement with experimental results.