Study was carried out to determine the yield losses (qualitative as well as quantitative) caused by (Oxycarenus laetusKirby) Dusky Cotton Bug (DCB) in cotton crop during July to October, 2011 and 2012 under field conditions in the area of Entomological Research Institute, Faisalabad. Different numbers of DCB viz., 0, 5, 10, 15, 20 and 25 pairs per boll were detained with muslin’s cloth bags. Observations were made on 100-seed weight, seed germination and visual staining of lint. Maximum lint discoloration (Slightly dark yellow during both the study years), reduction in cotton seed germination (28.2 & 32.13%) and reduction in seed weight (18.12 & 20.62%) were obtained during the study period (2011 and 2012, respectively) when population of dusky cotton bug was maintained as 25 pairs per boll.