In seven certified organic farms in Kurpie, Podlasie and Brodnickie Lake District regions of central and northen part of Poland, field performance and yielding potential of 32 currently cultivated and older cultivars and populations of (Triticum spelta), emmer (T. dicoccum), einkorn (T.monococcum) and bread wheat (Triticum aestivum) were studied. Plants were grown on plots 1m2 each. They were surveyed with respect to phases of plant growth, disease resistance, lodging resistance and yield parameters. Mean fungial diseases resistance to brown and yellow rust, septoria leaf blotch and powdery mildew of winter wheat species in 2005 under organic farming conditions was relatively high, except that relatively weaker resistance to yellow rust for bread wheat cultivars and spelt wheat was observed. One-year results show that level of yielding under organic farming was related to wheat species and soil quality. The best yielding potential under organic farming conditions was shown by modern bread wheat cultivars Mewa (630 g/m2) and Korweta (580 g/m2), which yields were higher by 23% and 14% above standard variety level. The best cultivars of Triticum spelta (v. album), showed yield potential similar to that of the average of old bread wheat cultivars (490 g/m2) which is 96% of that of the standard variety yielding level. The emmer variety yield reached 410 g/m2.