Tetrabutylammonium hydrogen sulfate catalysed addition of indoles to electron deficient olefins in water generated the corresponding Michael adducts in good to excellent yield. The Michael addition of indole occurred regioselectively at position 3 and the N-alkylated products have not been observed. The synthesized compounds were tested for their antibacterial activity against four microorganisms namely, E. coli NCIM 2931, S. aureus NCIM 5021, P. vulgaris NCIM 2813, P. aeruginosa NCIM 5029 by micro dilution method. These compounds showed MIC (Minimum Inhibitor Concentration) values in the range of 0-16-2-67 μM. © Indian Academy of Sciences.