Small lungworm infections of sheep are often detected at post-mortem examinations and at abattoirs but thought unimportant because they cause few obvious clinical signs. However, heavy lungworm infections may cause production loss, either directly or by worsening other respiratory diseases, such as pneumonia. Thus suggesting that treatment or prevention may be warranted if prevalence is high. It is thought that anthelmintics have some effect, but largely strategies for the treatment and prevention of small lungworms have not been described in the Australian context. Two species of small lungworm occur in sheep in Australia, Muellerius capillaris and Protostongylus rufescens, which require a mollusc intermediate host to complete their lifecycle. This paper presents the effect of pasture molluscicide treatment on the prevalence and severity of small lungworm infections, and the productivity of lambs grazing improved pastures in southeast South Australia. The findings of the snail population, the lucerne pasture availability, small lungworm infection levels within lambs, and lamb growth rates will be presented.