Crude ethanolic extracts of fruits, leaves, stems and roots of Citrullus colocynthis Schrad were examined for their antibacterial potentialities against Gram positive and Gram negative bacilli. Ethanolic extracts of fruits, leaves, stems and roots were found to be active against Gram positive bacilli, viz., Bacillus pumilus and Staphylococcus aureus, while fruit and root extracts in double strength gave positive results against Gram positive bacillus (Bacillus subtilis). The Gram negative bacilli viz., Escherichia coli and Pseudomonas aeruginosa showed no response.