In southern China, the awareness of persistent organic pollutant contamination has been increasing as a considerable number of past studies in Hong Kong had reported their trail in the coastal sediments, green-lipped mussels, muscle and viscera of pond fish, and foodstuffs. Hence there is an urgent need to assess their existence, contamination profiles, and potential impact on the public. In the present study, a survey was conducted to examine p,p'-DDT, p,p'-DDE, beta-HCH, and PCB concentrations in human breast milk, one of the most reliable bioaccumulation indicators. Milk samples (115 from Hong Kong and 54 from Guangzhou), in the lactation period from 3-5 weeks were analyzed. The results demonstrated that the mean levels of p,p'-DDT (Hong Kong: 0.39; Guangzhou: 0.70 microg/g of fat), p,p'-DDE (2.48; 2.85), and beta-HCH (0.95; 1.11) were 2-15-fold higher when compared with studies conducted elsewhere ( i.e., United Kingdom, Germany, Sweden, Spain, and Canada), and in contrast the concentration of PCBs (0.035; 0.031) was about 10 times lower. When compared to a similar study conducted 10 years ago in Hong Kong ( p,p'-DDT 2.17 microg/g of fat, p,p'-DDE 11.67, beta-HCH 15.96, and PCB 0.64), a considerable reduction in the levels of their contaminations was observed. The drastic reduction in body burdens in 10 years' time is presumably the result of effective regulatory actions. It is worth noting that body burden correlated positively with maternal age (total DDT, r = 0.93; beta-HCH, r = 0.91; PCBs, r = 0.77) and with historical record of seafood consumption (total DDT, r = 0.89; beta-HCH, r = 0.98; PCBs, r = 0.91) (p < 0.001) and potential uptake of the POPs by breastfed infants may pose adverse health hazards.