Plants have been a source of herbal remedies throughout the history of mankind. Various medicinal plants have been used for years in daily life to treat diseases all over the world. In the present study, antimicrobial activity of Azadirachta indica was evaluated against gram negative pathogenic bacteria (Escherichia coli, Salmonella typhi and Vibrio cholerae) and gram positive bacteria (Bacillus subtilis). Azadirachta indica leaves and barks were collected from the fields of Botanical Garden in Padmashri Vikhe Patil College, Pravaranagar and pure cultures of the test organisms used for antimicrobial study were obtained from the Dept. of Microbiology, Pravara Institute of Medical Sciences, Loni. All the test organisms were screened for their antibacterial activity against leaf and bark extract of A. indica by agar well diffusion method. Leaf and bark extract of Azadirachta indica showed more inhibition zone against Vibrio cholerae and Bacillus subtilis, while E. coli and S. typhi are less susceptible to neem extract.