Despite interest in the potential for fine fibre production from South American camelids in general and guanacos (Lama guanicoe) in particular there is little information currently available which would be relevant to their integration into UK livestock production systems. Without an understanding of their grazing behaviour on UK swards it is impossible to develop effective grazing management systems. This experiment was set up to compare the diet composition of guanacos and sheep when grazing a comparatively heterogeneous indigenous grassland community.