During the 20th century large areas of ancient semi-natural woodland were converted to conifer plantations, creating sites now termed PAWS (Plantations on Ancient Woodland Sites). Restoration of these sites to native woodland is a current objective of forestry policy throughout Great Britain. Natural regeneration is often regarded as the preferred method for restocking PAWS but it is a generally unpredictable process and some native species are very difficult to regenerate. A survey of western hemlock PAWS, carried out to identify which species were regenerating and how much of each was present, found a wide range of species either as seedlings or saplings, but at many sites the regeneration was predominantly birch. There were significant relationships between some site characteristics and the occurrence of regeneration, with the presence of nearby parents being especially important. Although there were often large numbers of seedlings present, most were small and patchily distributed, and the proportion of each site stocked with natural regeneration was low. A simple method for determining the proportion of a site stocked is described. While timber species such as oak and beech were regenerating, both seedling numbers and the areas of each site stocked were low. This indicates that natural regeneration may be an inadequate method of restocking and that planting may be required if an objective of management is to produce a good final crop of timber.