The organic carcinogens benzo(a)pyrene, dieldrin, and N-acetyl-2-aminofluorene were recovered on XAD-2 macroreticular resin in yields of 90 percent or more from distilled water or seawater and in yields of 40 percent or more from Lake Pontchartrain water containing a high concentration of organic material. The original solutions contained less than 500 parts per trillion of carcinogen. These results show that XAD-2 provides an efficient means for recovering nonpolar organic carcinogens from dilute solutions. More polar carcinogens such as dimethylnitrosamine were not effectively recovered on XAD-2 columns. Since XAD-2 binding would not be selective for carcinogens, the authors investigated methods which might bind carcinogens selectively from a mixture of organic compounds. We tested the ability of the above carcinogens to bind to nucleic acid using direct binding, equilibrium dialysis, nuclei binding, and binding to DNA-cellulose. Radio-labeled carcinogens were used to quantify the amount bound. Either rat liver nuclei (0.1 mg DNA) or DNA-cellulose (1 mg DNA) bound 18 percent of the acetylaminofluorene and up to 66 percent of the dieldrin from solutions containing 150 to 280 nmoles of compound. Up to 30 percent of the benzo(a)pyrene from solutions containing as much as 320 pmoles was bound. Ten-fold or lower recoveries were found when direct-binding or equilibrium-binding methods were used.