The primary objective of Angora goat producers is to optimise yields of high quality mohair, characterised by long staples of fine fibres. There is also now an increased interest in the concurrent production of goat meat as an additional source of income. Protein supplementation has been shown to affect mohair yield, quality and liveweight gain in Angora goats both in the USA (Shelton and Huston, 1966) and more recently in the UK (Shahjalal et al., 1991). Throckmorton et al. (1982) detected an improvement in liveweight gain and fibre production when Australian Angoras were fed a supplement high in rumen undegradable protein (UDP) but the effect of protein degradability has not yet been established, particularly under UK conditions. The aim of this trial was to determine the effect of varying protein degradability on yield, staple length and fibre diameter of mohair, and on liveweight gain of British Angora goats.