The purpose of our study was to estimate the interaction between N fertilization and a plant protection program in oat production under different weather conditions. The studies were conducted at the Grabów Experimental Station of the Institute of Soil Science and Plant Cultivation in Puławy, Poland, in 2005-07. Oat was cultivated after winter triticale at 5 different levels of nitrogen fertilizers: 0, 30, 60, 90, and 120 kg N·ha^-1 and under 3 plant protection strategies: A, B, and C were differentiated by biologically active ingredients. Grain yield, its components and quality were examined. The maximization of oat productivity and grain quality can be possible only under proper moisture conditions at a period from the beginning of the tilling stage (BBCH 21) to the end of panicle emergence (BBCH 59). The component deciding grain yield is a high number of grains per panicle. Both nitrogen fertilization and plant protection have a combined effect on oat grain, protein, and oil yields. Maximum grain yield increase equaled 2.26 t·ha^-1, protein yield 282 kg·ha^-1, and oil yield 73 kg·ha^-1.