The paper presents the effect of canopy protection methods on the yielding and weed infestation of thyme. The experiment also involved the analysis of forecrop influence on the quality and weed infestation degree of this plant. The field research was carried out in the years 2000– 2002 in Jaroszewice (Central Lubelszczyzna). The experimental field was situated on light and sandy clay soil (good wheat complex). The soil was characterised by light acid reaction, very high content of phosphorus, potassium and magnesium. Humus content was 1.26%. Three protection methods (mechanical, chemical and mechanical-chemical) were considered in the experiment. The other factor of the experiment was the beginning of thyme forecrops – potato, winter wheat and field pea + spring vetch mixture. In the chemical protection the following herbicides were used: Reglone Turbo 200 SL (before emergence) and Goltix 700 SC (after emergence of thyme). Mineral fertilization on all treatments was identical: N – 80, P – 17.5, K – 83 kg ha-1. It was proved that the highest decrease of thyme canopy weed infestation was obtained thanks to complex protection (mechanical and chemical). The herbicides reduced the number of dominant weeds species: Chenopodium album, Galinsoga parviflora, Thlaspi arvense and Capsella bursa-pastoris. Goltix 700 SC herbicide used in 3 leaves stage of thyme showed good selectivity in crops of this plant. The cultivation of thyme before potato forecrop stimulated the highest yield and raw material quality. Winter wheat turned out to be the worst forecrop, limiting the herbage yield and increasing canopy weed infestation.