Two studies investigated the use of non-speech sounds (auditory icons and earcons) in non-visual interfaces to MS-Windows for blind computer users. The first study presented sounds in isolation and blind and sighted participants rated them for their recognisability, and appropriateness of the mapping between the sound and the interface object/event. As a result, the sounds were revised and incorporated into the interfaces. The second study investigated the effects of the sounds on user performance and perceptions. Ten blind participants evaluated the interfaces, and task completion time was significantly shorter with the inclusion of sounds, although interesting effects on user perceptions were found.