Biologically active compounds in plant extracts play an important role in herbal medicine through their antimicrobial properties. Strychnos potatorum belongs to the family Loganiaceae. The seed is primarily used in the Indian traditional systems for several treatments including microbial infections. It is used in Ayurveda for treating the eye and urinary tract infections and in Unani for gonorrhoea and kidney troubles ,leucorrhoea, tuberculosis, venereal diseases and in Siddha medicine for acute diarrhea. Present study was to determine the In Vitro antibacterial activity of different seed extracts of Strychnos potatorum and test for the presence of phytochemical constituents. Cold, hot and ethanol seed extracts of Strychnos potatorum were tested for In Vitro antibacterial activity against Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853 , E coli ATCC 25922 and Enterococcus faecalis ATCC 29212 by using the standard agar well diffusion method. Distilled water and ethanol as solvent were used as control. Qualitative phytochemical analysis of extracts was also carried out for the presence of bioactive compounds using standard procedures. Results indicated that Cold, hot and ethanol extracts of Strychnos potatorum seed exhibited antibacterial activity among the tested bacteria. Cold seed extract failed to inhibit the growth of Staphylococcus aureus and Pseudomonas aeruginosa where as hot seed extract did not inhibit only the growth of Pseudomonas aeruginosa. But ethanol seed extract inhibited the growth of gram positive and all gram negative bacteria. Growth of Enterococcus faecalis(35.67±1.15) and E.coli (21.67±0.354)was significantly inhibited by ethanol seed extract rather than the growth of Staphylococcus aureus(16.24±0.653). Hot seed extract significantly inhibited the growth of Enterococcus faecalis(22.67±1.15). Phytochemical analysis indicated that Terpenoids and Saponins were present in all three extracts. Steroids and Flavanoids were only absent in hot extract. But ethanol extract contained all the tested phytochemical constituents. Further studies on sequential extraction and purification of antibacterial compounds in seeds could be developed.