In this report, we describe the synthesis of halogenated benzenesulfonamide compounds and their ability to inhibit the growth of HeLa, MCF-7 and MCF-7/ADR tumor cells in vitro. The multidrug resistance (MDR) phenotype of certain cells does not affect their sensitivity to these compounds. These agents belong to a family of compounds previously shown to bind irreversibly to cysteine-239 of beta-tubulin. Consistent with this mechanism of action, the cytotoxicities of these compounds appear to correlate with their ability to undergo nucleophilic aromatic substitution.