The possible utilization as food of linseed oil containing a large proportion of a-linolenic acid, an n-3 poly unsaturated fatty acid, was studied. Linseed oil was oxidized very slowly during storage at 4°C, so we judged that it could be stably kept for 8 weeks at 4°C. Linseed oil was gradually oxidized at 20°C, but the addition of roasted sesame oil was effective for suppressing this oxidation. The fatty acid composition of linseed oil scarcely changed during the storage, showing that the content of α-linolenic acid was more than 50%. Mayonnaise made from linseed oil remained stable in are frigerator and its composition scarcely changed during 8 weeks. The addition of roasted sesame oil to the mayonnaise further improved its oxidative stability and acceptability.