The aim of the publication was to find an answer to the question whether the market mechanisms present since 1990 have caused a change in the relations of prices to costs in the protection of wheat in years 1970-1994. The research concerned the following relations of prices to costs: W1 - relations of costs of pesticides to the price of the protected product, W2 - relations of costs of pesticides to the value of the protected production. In order for the changes of relations in time to be examined, two ratios (indexes) of dynamics have been used. The research has shown that the best dynamics of costs in the protection of wheat per 1 ha characterizes herbicides. The profitability of the protective treatments determined by the ratio of cost coverage per dt of the protected product and the share of the cost coverage of the pesticides in the value of the crop (in %) has remarkably decreased after the introduction of free market economy.