Plants and plant products are continuously being explored in medicine against the increasing number of antibiotic resistant organisms. The antimicrobial activity of essential oil of some plants has been demonstrated against a range of organism. This study aimed to determine the chemical constituents and the antimicrobial effects of the oil of grape peels on some clinical isolates. The oil was obtained from the peels by hydrodistillation procedure and analyzed using Gas chromatography coupled to mass spectrometer. The in-vitro antimicrobial property of the methanolic, ethanolic and tween 80 mixture of extract was determined by agar well diffusion method against selected clinical bacterial isolates (Bacillus cereus, Enterococcus faecalis, Escherichia coli, E. coli ATCC 25292, Klebsellia pneumonia, Pseudococcus sp., Salmonella typhmurium, Shigella flexneri, Staphylococcus aureus, Staphylococus aureus ATCC 29213) and fungal isolates (Aspergillus niger, Candida albican, and Penicillium chrysogenum). The GC-MS analyses of the oil indicated the amount of the essential oil components was highest with D-Limonene (75.05%), followed by β-myrene (7.25%), α-pinene (2.11%), caryophyllene (1.88%), octanal (1.68) and β-phellandrene (1.18%). Some of the minor components included δ-cadinene (0.89%), copaene (0.82%), methyl phthalate (0.54%), linalool (0.48%) and 3-carene (0.21%). The oil extracts exerted different degrees of inhibitory activity against the organisms. The inhibition of the test isolates was dependent on the dissolution solvent used. Methanolic oil mixture inhibited all bacteria and fungi. Ethanol oil mixture inhibited the test bacteria and C. albicans while, the oil extract dissolved in Tween 80 solution showed no inhibitory activity on the test fungi. This study has shown that grape peels from Nigeria contain some antibiotic principles which may be explored for use in the treatment of certain diseases.