Abstract: The field experiment was conducted at Students Farm, Sindh Agriculture University, Tandojam, Pakistan during 2004-05. Weed densities tested were: weedy check (control), wheat + Natural weeds (weedy for full season), wheat + mixed weeds (Chenopodium album, Melilotus alba, Avena fatua, Phalaris minor) (2:1), wheat + Chenopodium album (2:1), wheat + Melilotus alba (2:1), wheat + Avena fatua (2:1) and wheat + Phalaris minor (2:1). Among the tested weed densities, Chenopodium album, Avena fatua, Phalaris minor, and Melilotous alba were found common and serious weeds in wheat crop and reduced the tillers production, height of plants, seed index, wheat biomass and grain yield. The highest effect of Chenopodium album was recorded which reduced the grain yield by 39.95%, followed by Avena fatua (36.48%), Phalaris minor (35.33%), natural weeds for full season (34.96%), mixed weeds (32.14%) and Melilotous alba (24.01%). It was concluded that weeds exhibit the economic yield losses to the wheat crop, which may range from 24-39.95% and these must be controlled during the full growing season of the crop for achieving satisfactory crop yields.