Ruminant products have been criticised for the possible adverse effects of their saturated fatty acids on human health. Conversely, the omega-3 polyunsaturated fatty acids, notably those in fish oils, have been identified as beneficial components of the human diet. Earlier studies have shown that a small, but useful, amount of forage α-linolenic acid (C18:3), an omega-3 fatty acid, appears in ruminant products (Wood and Enser, 1996). The objective of the current work was to evaluate the range of α-linolenic acid concentrations in laboratory grass silages in order to assess the opportunities to modify ensiling techniques to increase the natural delivery of omega-3 fatty acid from grass silage to milk or meat.