Field studies were conducted in phosphate mined areas of Polk County, FL, to determine the responses of mosquitoes produced as a result of mining operations to octenol and carbon dioxide. There was a highly significant response of all species except Culex erraticus and Anopheles quadrimaculatus to CO2. Also, a significant negative octenol response was shown for An. quadrimaculatus. Coquillettidia perturbans, Mansonia titillans and Cx. salinarius had an increased response to octenol relative to no attractant. There was a slightly negative interactive effect between octenol and 500 cc/min CO2 for Anopheles spp. and Culex (Melanoconion) spp. Both Cq. perturbans and Ma. titillans showed a significant synergistic enhancement in catch with octenol supplemented CO2 when compared with CO2 alone. However, their response to CO2 was not significantly different at 2 release rates (200 and 500 cc/min). There was a slightly greater than additive effect for the combination of octenol and CO2 for Cx. nigripalpus.