Field experiments were carried out at Sids Research Station, Agricultural Research Center during 2016 and 2017seasons to determine the critical period of weed competition in pepper yield and study the effect of some pre-emergence herbicides on controlling weeds and its reflection on yield and its component of pepper. It could be concluded that some safe alternatives to mechanical weed control hand hoeing (twice), are the use of mulching by black polyethylene or reduced rate of pendimethalin (0.850 L.\fed) and butralin (1.25 L.\fed.) for weed control during the pepper crop to produce good fruit yield free from herbicidal residues. Mathematical models between weed-free duration periods were quadric 8.3 and 7.0 weeks from transplanting. The application of pendimethalin at 0.850 l.\feddan supplemented with one hand hoeing and black polyethylene mulch were the best treatments to reduce weed biomass, followed by hand hoeing twice and butralin at 1.25l.\feddan supplemented with one hand hoeing to face weed problem in critical period of weed competition and herbicidal residues in edible pepper fruits were below the maximum residue limit. The relationship between all characters were negatively and significant correlated with weed biomass and positive with pepper fruit yield in both seasons. Practical implications of this research are that planting pepper need weed management in 8 weeks from transplanting from weed competition which can be achieved by either the use of pendimethalin or butralin at a full recommended rates or followed by one hand hoeing or black polyethylene mulching to prevent early weed competition to pepper crop.