For producers of winter wheat the main purpose is to obtain high yield ensuring profitability. However, as the grain yield is concerned, profitability depends to a considerable degree upon its high quality giving a chance to obtain a higher selling price. The high grain quality is influenced by numerous factors. In the performed research work the influence of climatic conditions and intensity of the development of fungal diseases on leaves, ears and stem bases was investigated. Four-year plot experiments with winter wheat cvs. Kobra and Mikon were conducted in the Agricultural Experimental Station of Warsaw Agricultural University at Chylice, Mazowieckie voivodeship. Fungicidal treatments were performed twice, at shooting phase (GS 30) and at the beginning of earing (GS 51) using the newest plant protection products designed for controlling complex of fungal diseases on winter wheat. Weather conditions in the experimental years were differentiated. This was particularly related to the periods of intensive growth and ripening of winter wheat (April – July), while the deficiency of rainfall markedly influenced the development of fungal diseases, as well as the quality of grain. In 2000 a severe drought occurred, in the years 2001 and 2003 weather conditions were similar to standard values, and in 2002 this period was characterised by relatively low rainfall. The above conditions affected the occurrence and severity of fungal diseases, as well as the amount and quality of grain yield. In the years 2000–2003 winter wheat grain yield in treatments with fungicidal protection was higher on average by 26.12% in the interval from 7.34% to 53.15% and thousand grain weight was higher on average by 11.47% in the interval from 2.00% to 22.12%.