Passive air samplers consisting of polyurethane foam (PUF) disks were deployed in a network of eight sites across agricultural and urban areas in the Province of Buenos Aires in Argentina to assess levels of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) during two sampling periods in 2006 and 2007. Concentrations (pg m(-3)) of PCBs in air ranged from BDL to 360, with an average at urban sites of Bahia Blanca (200 +/- 130) about one order of magnitude higher than at agricultural sites in the Province of Buenos Aires (20 +/- 20). Endosulfan exhibited the highest concentrations of all the chemicals investigated with a maximum of 16 000 pg m-3 in the agricultural area. The remaining OCPs had lower levels (pg m(-3)) in the following ranges: Sigma HCH (alpha- + gamma-hexachlorocyclohexane) from 1 to 50, HEPT (heptachlor) and HEPX (heptachlor epoxide) from BDL to 20, chlordanes (Strans-chlordane, cis-chlordane and trans-nonachlor) from 1 to 40, dieldrin from BDL to 30, and p, p' -DDE (the only isomer of DDT that was detected) from BDL to 20. Concentrations of OCPs in air were highest at Bahia Blanca city and generally higher during the warmer sampling period. This study is one of the first investigations of the POPs composition in ambient air in the Province Buenos Aires of Argentina. The results support the Global Monitoring Plan of the Stockholm Convention on POPs and specifically, the need for air data to contribute to the regional report of the GRULAC (GRoUp of Latin American and Caribbean countries) region.