Antimicrobial resistance of bacteria is one of the biggest problems worldwide. Calotropis procera has been used in traditional and folk medicine due to presence of different active compounds. The present study was conducted to determine the antimicrobial activity of crude aqueous Calotropis procera extracts against field isolates of some gram negative and positive bacteria. The aqueous extract of the Calotropis procera was studied for its Antimicrobial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pyogenes, Salmonella typhimurium, Samonella arizonae subsp.3A, Salmonella typhi and Salmonella pullorum. In vitro antimicrobial activity was conducted by Kirby-Bauer disc diffusion technique on Mueller-Hinton agar. The extracts pronounced significant effect on the tested organisms. highest Zone of inhibition –mm (ZI) (35.4 ± 2.4) was in latex extract. There was a statistically significant (P < 0.05) difference between groups of bacteria in the antimicrobial effect of latex, leaves and flowers extracts. ZI of Latex, leaves and flowers extract for Salmonella typhimurium isolated from sheep was 7.667±.3, 3.583 ±.3 and 2.167±.2 respectively at Minimum Inhibitory Concentration (MIC) of 6.3 mg/ml. We concluded that the extracts of Calotropis procera has an antimicrobial activity against gram positive and negative bacterial isolates. The latex extract had more antimicrobial activity than leaves and flower. in addition, the leaves extract had more antimicrobial activity than flowers. (MIC) of Calotropis procera extracts was 6.3 mg/ml. It has been recommended to conduct further investigations in vivo to know the extent of the effect and control measure on salmonellosis and others bacterial diseases