Seed quality refers to a number of seed properties which may have varying degrees of practical importance for agriculture. As well as the traditional purity and germination capacity of seedlots, seed quality also includes species purity, cultivar purity, vigour, seed size, seedlot uniformity, seed health and seed moisture content. The quality of New Zealand herbage seedlots is reviewed. Data are presented for weed seed contamination, germination, seed vigour and seed weight. The influence such factors as analytical and cultivar purity, freedom from weeds, vigour and seed health have on New Zealand's domestic and export seed trade is discussed. Keywords: Seed quality, herbage seed, analytical purity, weed seeds, cultivar purity, germination, vigour,