An on-farm test for canola (Brassica napus L. and B rapa L.) seed vigor would help ensure that canola growers plant only high-quality seed. A rapid, 24-h color test based on ethanol emission by partially imbibed canola seed is described. Test results were compared to seed vigor measured as 2-d radicle protrusion (R2) and to standard germination (SG, normal seedlings). Color development was insensitive to variations in seed pesticide treatments, sample size (1-4 g), incubation temperature (19-26°C), incubation period (24-30 h), and initial seed moisture (5%-10%). The test partitioned seed samples into deteriorated and non-deteriorated categories for hybrid, open-pollinated, B. napus and B. rapa seeds with 84%–100% accuracy. The test was 86% accurate at classifying samples by R2 and 70% accurate at classifying sample by SG. Precision of repeat determinations was sufficient to permit single assays. Although further study is required, the assay appears to have promise as a practical on-farm seed vigor test.