A case control study was nested within a longitudinal study of faecal soiling on eight commercial farms in the south west of England. Eighty-two incident cases of faecal soiling in lambs between two and six months of age were individually matched with a single unaffected control lamb. A range of variables was examined including sex, neonatal history, trace element concentrations in blood, wool characteristics and faecal bacteriology and parasitology. Odds ratios and their 95 per cent confidence limits were estimated by using Mantel Haenszel methods and conditional logistic regression. Faecal soiling was significantly associated with longer fleeces, lower crimp frequencies, male lambs and multiple births. Significant relationships were also found between faecal soiling and neonatal diarrhoea, blood selenium concentration and the presence of Clostridium perfringens type A in the faeces.