In previous studies, a single isolate of P. recondita developed more slowly on winter wheat [Triticum aestivum] cultivars ''Purdue 6028A2-5-9-6-1'' (P6028) and ''Suwon 85'' than on ''Suwon 92'' and ''Monon''. The development of 22 isolates of P. recondita on these 4 cultivars was measured in a growth chamber to test the race nonspecificity of the slow leaf-rusting resistances of ''P6028'' and ''Suwon 85''. For a given isolate of the pathogen, only cultivars that developed a susceptible reaction type were compared. Thus, the development of 5 isolates on ''P6028'' and 21 isolates on ''Suwon 85'' was compared to their development on ''Monon'' and ''Suwon 92''. For all 5 isolates on ''P6028'', and for 17 isolates on ''Suwon 85'', the latent period was longer, a lower percentage of infection sites developed into pustules, there were fewer pustules per unit area of leaf, and pustules were smaller at 10-14 days after inoculation than on ''Monon'' or ''Suwon 92''. The other 4 isolates were exceptions to these trends because of greater resistance to them by ''Monon'' and ''Suwon 92''. The development of these 4 isolates on ''Suwon 85'' was similar to the development of the other 17 isolates on this cultivar. Final pustule size was similar on all cultivars, although pustules reached this size on ''P6028'' and ''Suwon 85'' later than on ''Monon'' and ''Suwon 92''. Slow leaf-rusting is race-nonspecific and should be long lasting.