Elastomeric parts found in automotive anti-vibration systems are usually massive. Ageing therefore leads to heterogeneous properties, usually induced by several mechanisms due to the availability, or not, of oxygen in the part’s bulk. To better understand the effects of oxygen in the degradation process and on the fatigue properties, this paper aims at studying the ageing of a rubber material (semi-efficient vulcanization system) in aerobic (with oxygen) and anaerobic (without oxygen) conditions for a wide range of temperatures, relevant for under hood applications. The material studied here is a fully formulated compound NR/IR blend reinforced with carbon black. A specific protocol to perform ageing under anaerobic conditions was set up and validated. Numerous tests have been carried out to evaluate the consequences of ageing on monotonic tension and fatigue properties. A comparison of these consequences and of their kinetics is finally presented for ageing with or without oxygen.