Vera, C. L., Duguid, S. D., Fox, S. L., Rashid, K. Y., Dribnenki, J. C. P. and Clarke, F. R. 2012. Short Communication: Comparative effect of lodging on seed yield of flax and wheat. Can. J. Plant Sci. 92: 39-43. Lodging may limit crop productivity and hinder the normal process of harvesting crops. Results from 16 yr (1994-2009) of the Flax Co-operative test and from 29 yr (1981-2009) of the Central Bread Wheat Co-operative test, conducted annually for the evaluation of advanced breeding lines at various locations in the provinces of Manitoba, Saskatchewan and Alberta, Canada, were used to determine the effect of lodging on the seed yield of these two crop species. Seed yield data were regressed on corresponding lodging scores (1-9 scale) collected from field evaluations. Lodging was more frequently a problem in flax (Linum usitatissimum L.) than in wheat (Triticum aestivum L.), with average seed yield reductions of 32% and 16%, respectively, when lodging was most severe. Disease has been observed in association with the occurrence of lodging in flax. Further research is necessary to elucidate the participation of airborne and soil microorganisms, particularly pasmo, caused by Septoria linicola (Speg.) Garassini, in the mode and degree to which flax is subjected to, and affected by, lodging.