Little is known about the levels of organochlorines (OCs) in predatory bird species from Asia or the factors governing their concentrations. This study is the first report on concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in predatory birds of Pakistan. The concentrations of PCBs and OCPs were investigated using tail feathers of ten different species of predatory birds. In addition, concentration differences among body, tail, primary and secondary feathers were investigated for six individuals of black kite (Milvus migrans). Ranges of concentrations were highest for dichlorodiphenyldichloroethylene (p,p'-DDE: 0.11-2163 ng g(-1) dry wt,) followed by dichlorodiphenyltrichloroethane (p,p'-DDT: 0.36-345 ng g(-1) dry wt.), hexachlorobenzene (HCB: 0.02-34 ng g(-1) dry wt.), Sigma PCBs (0.03-16 ng g(-1) dry wt.) and trans-nonachlor (TN; 0.01-0.13 ng g(-1) dry wt.). CB 118, 153,138, and 180 along with p,p'-DDE were found as the most prevalent compounds. Sigma PCBs and Sigma DDTs were significantly different among species (both p < 0.01) and omnivorous, scavengers, carnivorous and piscivorous trophic guilds (all p < 0.03). Only Sigma PCBs were significantly clifferentamong different families of birds (p <0.01). Values of stable isotopes (delta C-13 and delta N-15) differed significantly (all p < 0.01) among species, families, trophic guilds as well as terrestrial and aquatic habitat but not between nocturnal and diurnal predators (p = 0.22 for delta N-13; p = 0.50 for delta N-15). Concentrations of Sigma PCBs, Sigma DDTs and trans-nonachlor, but not HCB (p = 0.86), were significantly different among different feather types (all p < 0.01). Trophic and taxonomic affiliation as well as dietary carbon sources (delta C-13) for species were identified as the variables best explaining the observed variation in exposure to the studied compounds. The significance of contributing factors responsible for OC contamination differences in predatory birds should be further elucidated in future studies