Objective: The aim of the current study was to evaluate antimutagenic (anticlastogenic) activity of methanolic extract of Lagenaria siceraria fruit, Desmodium gangeticum and Leucas aspera. Method: The group distribution for animal was, negative control, only extract treated,positive control (cyclophosphamide treated), and two treatment control group for each plant extract. Mutagenicity was induced byadministering cyclophosphamide (20-25 mg/kg, i.p) 24 hrs prior to sacrify animals. Result: The preliminary phytochemical tests showed presence of alkaloids, polyphenols, flavanoids and tannins in alcoholic extract. It’s antioxidant and cytoprotective activity of the extracts has already been reported. On thebasis of that we have decided to evaluate its antimutagenic activity in vivo in miceusing bone marrow chromosomal aberration assay. Methanolic extract of selected plants had shown significant reduction in percentage of cells with aberration in chromosomal aberration assay. Theresults obtained by these experiments, strongly suggesting that Lagenaria siceraria fruit extract having potent antimutagenic property than desmodium gangeticum and Leucas aspera. The overall antimutagenic activity of above three extract were in the order of Lagenaria siceraria>Desmodium gangeticum>Leucas aspera. The observed antimutagenic activity of selected plant against Cyclophosphamide might be associated with itsantioxidant constituents such as poly-phenolic compound, flavanoids and other micronutrients. Conclusion: Therefore, from the present study, it can be concluded that methanolic extract of selected indigenous plant extract possesses antimutagenic property.