Aqueous and acidified methanol extracts from C. limonum fruit residues (CLFR) were evaluated for their total phenolic contents, antioxidant and antimutagenic activities. Total phenolic contents (TPC) of aqueous (30% and 70%) and acidified (0.5 N and 1.0 N) methanol extracts from CLFR were estimated by Folin- Ciocalteu reagent method whereas in-vitro antioxidant activity was assessed calorimetrically by measuring DPPHscavenging capacity and inhibition of linoleic acid peroxidation. Anti-mutagenic potential of the extracts was appraised by Ames bacterial reverse mutation test. TPC, DPPH° scavenging capacity and inhibition of linoleic acid peroxidation were varied from 27.75-126.35 mg gallic acid equivalent (GAE)/g DW, 46-91%, and 34-83%, respectively. All the tested extracts of CLFR noticeably hunted mutagens (16.47-55.69 %) whereas none of these caused mutagenesis. Overall, acidified methanol extracts from CLFR exhibited higher extraction yields, TPC, inhibition of peroxidation and DPPH radical scavenging activity among others indicating a significant ( p<0.05) variation of these attributes in relation to residue samples and extraction media. The results support that CLFR (peel and pulp biomass) being a rich source of phenolic antimutagens, can be explored as a potential candidate for the development of natural chemo-preventive drugs and nutracueticals. . Due to presence of pharmaceutically important compounds, especially phenolics, citrus can be a potential source of ingredients for the development of chemotheruapic drugs and nutracueuticals but extraction of such bioactive compounds due to their structural complexity is a challenging task. In our recent study, we observed that aqueous methanol was a good choice for the extraction of citrus fruit phenolics but the recovery rates was not promising 11 . The reason might be the presence of covalent linkage between phenolics (bound phenolics) and cell wall constituents. Conventionally, organic solvents such as methanol and ethanol are known to be efficient for the extraction of free phenolics (entrapped) but these solvents are often unable to extract and liberate citrus bound phenolics (more than 20 % phenolics are in bound form) from the well-organized cellulosic cell wall structure further fortified by lignin and in certain cases shielded by pectin 10 . During the present study, therefore, a simple acid hydrolysis based process was applied to facilitate the liberation of bound phenolics from citrus fruit residues (peel and pulp biomass) during aqueous methanol extraction. Moreover, the extracts produced by different concentrations of acidified methanol were evaluated for their phenolic contents as well as antioxidant and antimutagenic activities using in-vitro assays.