Background: Zingiber officinale Roscoe (Zingiberaceae) is a rhizomatous perennial herb found in tropical Asia. It is extensively used worldwide as a spice, flavoring agent and herbal remedy for cold, throat and chest infections and cough. The present study was carried out to analyse an essential oil from the fresh rhizomes of Z. officinale of Ghaziabad region and to evaluate its antimicrobial activity. Materials and Methods: The fresh rhizomes were hydrodistilled to get the essential oil which was analysed by GC and GC-MS techniques. The oil was evaluated for antimicrobial activity by disc diffusion method. Results and Discussion: The essential oil was characterized by high percentage of sesquiterpenes (66.66%), monoterpenes (17.28%) and aliphatic compounds (13.58%). The predominant sesquiterpene was zingiberene (46.71%) followed by valencene (7.61%), β-funebrene (3.09%) and selina-4(14),7(11)-diene (1.03%). The major monoterpenes were characterized as citronellyl n-butyrate (19.34%), β-phellandrene (3.70%), camphene (2.59%) and α-pinene (1.09%). The essential oil exhibited significant antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger. Conclusion: The essential oil mainly contained a large number of sesquiterpenes and monoterpenes and exhibited significant antimicrobial activity against pathogenic microorganisms.