Abstract: Biological control is the most important component of IPM because a number of pests of a crop, remain under natural control if crop is unsprayed. Many natural enemies such as predatory beetles, bugs, lacewings and spiders have been recorded in cotton fields in Sindh Pakistan, but their potential value has been widely exploited in cotton pest management due to lack of techniques to conserve and maximize both their abundance and effectiveness. During 1999 cotton season population dynamics studies were carried out to observe the beneficial insects under sprayed and unsprayed conditions at Sakrand Sindh. Three spray applications were given in sprayed block with Dimethoate 40 EC, Thiodan 35 EC and Tracer 480 SC against sucking and bollworm complex of cotton. Predators appeared 10 days after germination of cotton plant. The species observed during the season were i.e. chrysopa, orius, geocoris, spiders, coccinellids, Zanchius and campylomma. The numbers of predators ranging from three to fifty six thousand in unsprayed plot and 0.7 to 8.9 thousands in sprayed block. These predators were active throughout the cotton season with a peak population during July and August.