The effects of the addition of oxygen to the feed of an ethane steam cracker for ethylene production were investigated at industrial conditions by means of experiments and computer simulations. The oxidation of a small fraction of ethane feedstock in the cracking coil generates a significant amount of heat which can be used by the endothermic pyrolysis reactions. With this, the heat-transfer limitation in the industrial crackers is released. The addition of oxygen increases the conversion of ethane, while the yield to ethylene decreases slightly. Simulations indicate that the effects of the oxygen addition can be beneficial to industrial crackers in three manners : decreased residence time or increased throughput, higher severity, or reduced tubeskin temperature and longer coil lifetime.