The initially stated objective of the Canadian dairy supply management–farm revenue risk reduction–has been met well by the program. However, it is less clear whether the program has served all farms equally well. Namely, it is not known how successful the program was in enhancing the cost-effectiveness of smaller farms. This paper uses the 2006 Ontario dairy farm-level accounting data to compare the estimated cost structure with that identified by Moschini (1988). Next, farm size and profit distribution changes are assessed. Finally, the paper provides a simple framework for examining the relationship between current farm size and quota purchases by individual farms. The results suggest that the general cost pattern identified in the early 1980s has been retained. Average cost declines as output increases at lower output levels. However, the minimum-cost farm size has increased about threefold. Additionally, both output and profit distributions have become more skewed, with a lesser contribution by smaller farms. There is evidence that the possibility of quota exchange facilitated the greater expansion of larger farms and that the process of divergence in size and profit between small and large farms is continuing. These results have bearing on the sustainability of smaller farms.