10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 1 2013 (January - March) The antimicrobial activity was evaluated on Gram positive bacteria- lessThan i greaterThan Staphylococcus aureus lessThan /i greaterThan (MTCC lessThan i greaterThan 3160) lessThan /i greaterThan , Gram negative- lessThan i greaterThan Escherichia coli lessThan /i greaterThan (MTCC 1652) and lessThan i greaterThan Pseudomonas lessThan /i greaterThan lessThan i greaterThan aeruginosa lessThan /i greaterThan (MTCC 647) and fungi- lessThan i greaterThan Aspergillus niger lessThan /i greaterThan (MTCC282), lessThan i greaterThan Aspergillus flavus lessThan /i greaterThan (MTCC 2456) lessThan i greaterThan , lessThan /i greaterThan lessThan i greaterThan Fusarium culmorum lessThan /i greaterThan (MTCC349) and lessThan i greaterThan Rhizopus stolonifer lessThan /i greaterThan (MTCC 2591). The dried leaf extract prepared in ethanol, methanol, petroleum ether and aqueous solutions were used to assess their antibacterial and antifungal potential in terms of zone of inhibition of bacterial growth. The petroleum ether extract exhibited highest zone of inhibition against lessThan i greaterThan P. aeruginosa lessThan /i greaterThan (20.3±0.92 mm) with low MIC value (24.5 mg/ml). Phytochemical screening of the extract showed the presence of alkaloids, carbohydrates, flavonoids, tannins and saponins. Results obtained in the present study indicate that lessThan i greaterThan Nyctanthes arbor-tristis lessThan /i greaterThan possess compounds with antimicrobial properties that can be used for plant based antimicrobial agents. ALPANA VYAS AND RENU SARIN Nyctanthes arbor-tristis, antimicrobial activity, zone of inhibition, phytochemical analysis. 201-206