To study the effects of integration of mechanical control with herbicides on yield and yield components of soybean (Glycine max) a field experiment was conducted during 2003-2004 at the research farm of Agronomy Department, Agriculture Campus of Tehran University, Karaj. A Randomized Complete Block Design (RCBD) of 18 treatments was applied, each treatment being replicated 3 times. Treatments included 5 groups, viz: 1-tifluralin pre planted (960 gr ai/ha), alachlor pre emergence (2400gr ai/ha), bentazon (1200 gr ai/ha) and oxyflourfen (360 gr ai/ha) both post emergence, 2-trifluralin and alachlor plus cultivation or tank mixed with bentazon and/or oxyflourfen, 3-trifluralin and alachlor, plus cultivation and a reduced dose of bentazon (960 gr ai/ha) and/or oxyflourfen (288 gr ai/ha), 4-Trifluralin (1920 gr ai/ha) applied with irrigation water (herbigation) separately, and tank mixed with bentazon or oxyflourfen, and finally 5-weed free check. There were significant differences between treatments regarding weed dry weight at the physiological maturity stage of soybean crop. Trifuralin + oxyfluorfen and alachlor with 95 and 56% control were among the most efficient treatments. Treatments varied significantly with number of lateral branches, 100 seed weight, number of pods/plant, biological yield and harvest index at P=0.01 and number of seeds/pod at P=0.05. The highest (10148 Kg/ha) and the lowest (2981 Kg/ha) biological yields were obtained when applying bentazon at 1200 g ai/ha and alachlor + cultivation + reduced dose of oxyfluorfen at 288 + 2400 g ai/ha, respectively. The highest (2940 Kg/ha) and the lowest yields were obtained when applying trifluralin + bentazon at 1200 + 960 g ai/ha and trifluralin + oxyfluorfen at 360 + 960 g ai/ha, respectively. Best treatments in terms of weed control and optimum yield are considered to be tank mixes of trifluralin and bentazon (1200 + 960 g ai/ha), trifluralin, (plus cultivation), plus a reduced dose of bentazon (960 + 960 g ai/ha).