This paper describes the results of a research aimed at investigating the fatigue resistance performances, determined by means of the four-point bending test (4PBT), of bituminous mixtures (SMA and traditional ones) for base courses and wearing courses, made with Electric Arc Furnace (EAF) steel slag and bitumen modified with crumb rubber or SBS polymers. The fatigue behaviour was also studied after long-term ageing, in order to check the effectiveness of the crumb rubber modification (by wet process) in reducing the fatigue damage in heavily oxidized mixtures. For both unaged and aged conditions, the asphalt rubber mixes presented better fatigue behaviour than the reference mixtures made with polymer modified bitumen.