Soil samples were collected from 30 farms in Alabama, Louisiana and Texas during 1999–2000 to determine residues of organochlorine pesticides (OCPs). One or more of the DDT compounds (p,p′-DDT, o,p′-DDT, p,p′-DDD, p,p′-DDE, o,p′-DDE) was above the quantitation limit (0.1 ng g −1 dry weight) in every soil, and toxaphene was above the quantitation limit (3 ng g −1) in 26 soils. Chlordanes, dieldrin and hexachlorocyclohexane (HCH) isomers occurred less frequently (quantitation limits 0.1 ng g −1 for dieldrin and 0.05 ng g −1 for chlordanes and HCHs). OCPs were measured in air at 40 cm above the soil at selected farms to investigate soil-air partitioning. Concentrations of OCPs in air were positively and significantly ( P<0.001–0.004) correlated to soil concentrations for toxaphene, p,p′-DDT, o,p′-DDT, p,p′-DDE, dieldrin, and trans-nonachlor. The regression was weaker ( P=0.022) for cis-chlordane and not significant for trans-chlordane ( P=0.43) nor γ-HCH ( P=0.80). Approach to soil-air equilibrium was assessed by calculating fugacities in the soil and air ( f s and f a) for samples with quantifiable residues in both compartments. The fugacity fraction f s f s +f a =0.5 at equilibrium and is <0.5 or >0.5 for net deposition and net volatilisation, respectively. Fugacity fractions varied greatly for different soil-air pairs, reflecting generally disequilibrium conditions. Mean fugacity fractions indicated near-equilibrium for some OCPs (p,p′-DDE, chlordanes, trans-nonachlor and dieldrin) and net volatilisation for others (p,p′-DDT, o,p′-DDT, toxaphene, γ-HCH). Chiral analysis showed that enantioselective degradation of (+) or (−) o,p′-DDT in soil was accompanied by enrichment or depletion of the corresponding enantiomers in the overlying air, although there appeared to be some dilution by racemic o,p′-DDT from regional air transport.