Technical Abstract: The swelling of wheat (Triticum aestivum L.) starch has an important effect on the quality of end-products, especially white salted noodles. We determined the genotypic and environmental variation for flour swelling volume (FSV) in spring and winter wheat varieties grown in up to 31 unique environments and 4 crop years. FSV ranged from about 19 to 30 ml g-1. Analysis of variance (ANOVA) of 8 balanced data sets indicated that variety was consistently a highly significant source of variation. Environments as unique combinations of locations and crop years were variably significant, as were locations, whereas crop years were always a significant source of variation. Only rarely were ANOVA interaction terms significant. Model R2's ranged from 0.87 to 0.98 for the data sets. Variety accounted for 36.1 to 93.3% of the total variation. Environments accounted for 1.7 to 61.7% of total variation. The relative variation assignable to the interaction terms never exceeded 10%. Penawawa was significantly the highest FSV variety. In conclusion, FSV is primarily influenced by variety and secondly by environment, crop year more so than location within a crop year. The small interaction of variety with environment suggests that variety development programs can easily identify and track desirable FSV types. Incremental changes in FSV were observed among the varieties and therefore optimum FSV occurring throughout the range encountered should be attainable in new, improved varieties.