Hay is a very common forage fed to horses in the UK with Hollands (2001) reporting it as the most common. The affiliation between hay and equine respiratory disease is well documented and McGorum (2001) states that 90% of hay made in the UK is of inadequate quality for consumption by horses. The process of soaking hay prior to feeding is well recognised to reduce the number of spores within the hay (Blackman and Moore-Colyer, 1998; McGorum, 2001). As a consequence soaking hay is common practice in many stable yards. This has many disadvantages including disposal of the post-soak liquor and the reduction in nutrient value of the hay (Blackman and Moore-Colyer, 1998). Steaming hay has been suggested as a potential alternative to soaking. There are currently few studies directly comparing the efficacy of soaking and steaming. This study aims to compare the impact of both soaking and steaming treatments on the levels of respirable particles and nutrients of hay.