In order to find dual antagonists against both thromboxane A2 (TXA2) and leukotriene D4 (LTD4) receptors for a new antiasthmatic agent, various benzenesulfonamide derivatives were synthesized and evaluated for those pharmacological effects. TXA2 and LTD4 antagonistic activities in vitro were evaluated by the inhibitory effects on LTD4-induced and U-46619-induced contraction of guinea-pig trachea. Furthermore, TXA2 and LTD4 antagonistic activities in vivo were evaluated by the inhibitory effects on LTD4-induced and U-46619-induced bronchoconstriction of guinea-pig after oral administration of test compounds. It was found that 4-[5-[1-(4-chlorobenzenesulfonamido)-5-methylhexyl]-2-thi eny l]butyric acid and 4-[5-[1-(4-fluorobenzenesulfonamido)-5-methyl-hexyl]-2-thienyl]but yric acid possess good anti-LTD4 and anti-TXA2 activities by oral administration.