The field experiment was conducted in 2004–2007 at the Experimental Station Uhrusk. The aim of the experiment was to examine the effect of chemical and mechanical plant for grain quality of spring wheat cv. Opatka. Weeds were destroyed using herbicides Puma Super 069 EW (fenoxaprop-P-etylu) and Aminopielik M 450 (2,4-D mecoprop-P), pathogenic fungi were controlled with Alert 375 SC (flusilazole + karbendazim) and Tilt CB 37,5 WP (propikonazole + karbendazim). Studied characteristics of wheat grain were: total protein, wet gluten, sedimentation, test weight, grain uniformity, falling number and crude ash. Chemical plant protection increased the amount of grain of spring wheat, total protein content, wet gluten and sedimentation in relation to mechanical protection. Chemical plant protection decreased the number of weeds and air-dry mass of weeds and leaf infestation by fungal diseases.