Abstract: Reducing the number of viable weed seeds entering a field is critical to successful weed management. Viable seeds can result from weed survivors that reach maturity, or can be imported into the field via livestock, grain, fodder, or machinery. Few reports exist on the survival of seeds in silage, or the consequence of feeding the silage to livestock. Seeds from five grass weeds, six broadleaf weeds and three pasture species were ensiled, underwent 48 hour in sacco digestion or both. Seed germination was determined after incubation at 25/15°C on a 12 hour temperature cycle. Tetrazolium staining was used to determine the viability of ungerminated seed. Seed germination and viability were compared with untreated seeds. Seed from all grass weeds except annual ryegrass were rendered unviable after being ensiled, whereas some broadleaf weed seeds remained viable. Digestion had a similar effect as ensilage on reducing seed viability, except for silverleaf nightshade and prairie ground cherry where no reduction in viability was observed. The viability of marshmallow seed and the three pasture species was not significantly reduced by either ensilage or digestion. Ensile or digestion can provide non-chemical options for effective weed management for certain weed species. [Rex Stanton, John Piltz, Craig Rodham & Hanwen Wu (2012). Silage for managing weed seeds. Eighteenth Australasian Weeds Conference, Melbourne, 8-11 October, 2012] ${imageDescription} Comment