In years 2004-2006 field performance and yielding potential of 4 currently cultivated varieties (Sławko, Chwat, Szakal, Polar) and 3 older cultivars (Proporczyk, Udycz Żółty, Tatrzański) of oats (Avena sativa L.), were studied. Plants were grown in plots of 1 m2 each, in ten certified organic farms in Kurpie, Podlasie and Brodnickie Lake District regions of central and northern part of Poland. They were surveyed with respect to disease and lodging resistance, yield and its parameters as the weight of 1000 grain and panicle height. Three-years results show that mean level of yielding under organic farming obtained from old oats cultivars was similar to that of the modern ones. The best yield was shown by cultivars Sławko, Szakal and Chwat, which showed the best tolerance to the precipitation deficit and significant higher 1000 grain weight. Naked oats Polar shown 50% level of yielding of hulled cultivars and his yield was significantly decreased by precipitation deficit. Old cultivars Proporczyk and Udycz Żółty show the best yielding from all varieties in favourable for oats cultivation year 2004. In the precipitation deficit conditions their yield tended to decrease slightly. Both old and modern oats cultivars tend to be excellent adopted to organic farming conditions, showing high yield and disease resistance.