Resistances to current antibacterial drugs are growing global concerns. The aim of this study was to identify the phytochemicals from the fruits, root and leaves of Citrulluscolocynthis and to study the antibacterial effect of aqueous and hydromethanolic extracts of leaves, roots and fruits. Phytochemical screening revealed the presence of some active substances including flavonoids, saponins and steroid. Aqueous and hydromethanolic extracts of fruits, leaves and roots of C. colocynthis Schard. were examined for their antibacterial potentials against Gram positive and Gram negative bacteria. All extracts show activity against all bacteria strains, the highest minimum inhibitory concentration (MIC) was obtained from the hydromethanolic root extract with 5.6 mg/ml against Klebsiella pneumonia and 6 mg/ml against Bacillus stearothermophilus and Staphylococcus aureus.