The objective of the present study was to investigate the antimicrobial activity of chloroform, ethyl acetate, acetone, methanol and ethanol extracts of Eruca sativa seeds growing in Saudi Arabia. Major chemical constituents and functional groups of E. sativa extract were determined by Gas Chromatography -Mass Spectrometry and Fourier Transform-Infra Red Spectroscopy analysis. Seed extracts showed potent antimicrobial activity against pathogenic bacteria and fungi. Ethyl acetate extract was highly efficient in controlling the growth of Staphylococcus aureus, Bacillus subtilus, Methicillin resistant Staphylococcus aureus, Streptococcus pyogenes and Escherichia coli. Maximum zone of inhibition was exhibited by S. aureus (26mm).Similarly, methanol extract showed strong inhibitory effects on mycelial growth of all the fungi tested except for Colletotrichum gleosporoides. Maximum mycelial inhibition (82%) was recorded for Colletotrichum musae. The minimum inhibitory concentration and minimum bactericidal concentration results demonstrated the efficiency of the extracts screened. Furthermore, micrographs from scanning electron microcopy revealed the damaging effects of extracts on cell morphology as blebs, indentation and complete lysis at 0.8mg/ml. GC-MS analysis of ethyl acetate and methanol extracts has led to identification of important compounds  which are known antifungals and antibacterials .