Samples of frost‐damaged rapeseed from the 1982 Western Canadian Crop were tested for oil content, protein content, fat acidity, chlorophyll content, fatty acid composition, glucosinolate content, conductivity and germination. These quality factors were related to two frost‐related damage factors, green seeds and external “frost‐damage,” used in the Canadian grain grading system. The green seed factor was positively correlated with chlorophyll, free fatty acids and conductivity, and a negative correlation was found with linolenic acid, iodine value and germination. The frost‐damage factor was positively correlated with conductivity, free fatty acids and palmitic acid and negatively correlated with linolenic acid, iodine value, oil content and germination. The effects of frost damage were explained by assuming that the seed maturation process was halted due to freezing.