The authors put forth their proposition for pesticide classification from the points of view of acute toxicity, skin irritation, skin toxicity 'resorption), cummulation coefficient and chronic effect--anticipated chronic risk. The proposition of this kind may be considered a priority in Czechoslovakia. It is confronted with the criteria for pesticide classification recommended by the WHO which it suitably completes. Acute toxicity makes it possible to classify pesticides into five classes: class I - highly toxic, class II - toxic, class III - moderately toxic, class IV - slightly toxic, class V - virtually non-toxic. Skin irritation enabled to classify pesticides as highly irritant, irritant, moderately irritant, slightly irritant and non-irritant. For skin toxicity 3 degrees were used: those of very good resorption, good resorption and low resorption. The proposition fr classification is supplemented by cummulation coefficient and the aspect of chronic effect. In the present study the authors call for further search for the criteria of pesticide classification and draw attention to some pesticides, discussing their re-classification into higher classification classes.