AbstractIn the last few years, the interest in sulfonamides has expanded owing to their broad spectrum of biological activities. Their flexible structure turns them into amazing candidates to replace old drugs or develop modern multi‐target agents. In this study, a series of new sulfonamides (sul1‐5) was evaluated, in vitro, for the antibacterial, cytotoxic and genotoxic effects. The antibacterial activity was investigated against 12 clinical and 4 reference strains. Cytotoxic activity was carried out by the brine shrimp bioassay and the genotoxicity was assessed in the Ames test. An interesting antibacterial activity was showed especially against Gram negative strains. The inhibition zones varied between 15 and 30 mm, and the Minimum Inhibitory Concentrations (MIC's) values between 0.5 and 256 μg/ml. No antibacterial activity was shown with S. aureus isolates. Only Sul1 and Sul4 were active against P. aeruginosa. Compounds Sul1 and Sul2 showed a significant cytotoxicity with LC₅₀ equal to 18.29 and 18 μg/ml respectively, and a genotoxic effect against TA100 and TA1535 Salmonella strains. Only compounds Sul3, Sul4 and Sul5 with an interesting antibacterial activity, no cytotoxicity and no genotoxic effects, could be exploited against resistant pathogens as new drugs.