Concentrations and congeners of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in forty-six municipal sludges derived from fifteen cities in the Yangtze River Delta Area of China were determined by gas chromatography (GC) after ultrasonic extraction and silica gel cleanup.PCBs concentrations ranged from non-detectable to 0.720 mg/kg (dry weight,DW) and averaged 0.076 mg/kg,with most sludges containing < 0.1 mg/kg.PCBs concentrations in only two sludge samples were > 0.2 mg/kg,the limit value for sludge applied to agricultural land in China.OCPs concentrations varied between non-detectable and 0.426 mg/kg (DW),with an average value of 0.055 mg/kg and most sludges contained < 0.05 mg/kg.Among PCBs,PCB44,PCB180,PCB99,PCB52,PCB74,PCB77 and PCB167 were most enriched in the sludges analyzed,and among OCPs,o,p'-DDT,p,p'-DDE,β-HCH,δ-HCH,α-HCH,γ-HCH,p,p'-DDD and p,p'-DDT were detected from major to minor.The congeners,concentrations and distributions of the two kinds of organic pollutants in the municipal sludges were related to sludge type,source and treatment technology,together with the physico-chemical properties of PCBs and OCPs.