The objective of the study was to analyze the efficacy of dimethenamid-p (Frontier Super) for the control of annual grass and broad-leaved weeds in sugarbeet (Beta vulgaris L.). The trial was conducted in 2000 on the localities of Zemun Polje. Dimethenamid (Frontier 900 EC) was the control herbicide. Both efficacy and phytotoxicity were assessed according to the standard EPPO method. The lowest application rate (0.8 l ha-1) was effective (75-90%) for the species Amaranthus retroflexus L. and Echinochloa crus-galli L.. Increasing the application rate to 1.0 l ha-1 tended to raise the efficacy (90- 100%). Further increase of the application rate to 1.2 l ha-1 proved the efficacy of the herbicide in controlling Polygonum lapathifolium L. as well, whereas in the case of Chenopodium album L. a favourable result was registered in the first assessment only. The efficacy obtained in the first assessment applying the highest application rate (1.4 l ha-1) was the same as using 1.2 l ha-1. However, in the second assessment the efficacy of the herbicide was low (0-75%) in controlling P. lapathifolium only. The efficacy of the herbicide for the control of all the other available species (Datura stramonium L, Hibiscus trionum L., Solanum nigrum L and Xanthium strumarium L.) was low even at the highest application rate (1.4 l ha-1). High resistance to the herbicide tested has most probably contributed to the unfavourable efficacy for some weed species such as: D.stramonium, H.trionum, S.nigrum and X.strumarium. Frontier Super should be applied at the lower dose rate than the control herbicide Frontier 900 EC in order to achieve the same efficacy. The reason for this is the purified active isomer dimethenamid in Frontier Super. However, Frontier 900 EC contains a mixture of isomers of the same compound. Therefore, current trends focused on decreasing the dose favour Frontier Super. The herbicide is economically justifiable and environmentally safe.