Essential oils obtained by hydrodistillation of the fruit rinds of Citrus jambhiri Lush. (Rough lemon) and C. pyriformis Hassk (Ponderosa lemon) were analyzed by capillary gas chromatography (GLC/FID) and gas chromatography-mass spectrometry (GLC/MS). A total of 94 compounds were unambiguously identified from the oils and the (hexane/ether) extracts of the rind and juices representing 98.55% and 97.98% of the total oil composition. The main component of both oils was D-limonene (92.48% and 75.56% respectively). The antioxidant, anti-inflammatory, antitrypanosomal, antimicrobial and cytotoxic activities of the essential oils were evaluated. Whereas Citrus jambhiri and C. pyriformis have antioxidant activity with IC50 +/- SD 37.69 +/- 0.21 mg/ml and 28.91 +/- 0.09 mg/ml, respectively. Ascorbic acid a known potential inhibitor for DPPH free radical an commonly used antioxidant showed an antioxidant activity with an IC50 value of 16.32 +/- 0.161 g/mI. Both oils inhibited the activity of 5-lipoxygenase (5-LOX) with an IC50 of 40 +/- 1.63 and 38 +/- 0.82 microg/ml, respectively, and could be considered as interesting candidates for antiinflammatory agents. The essential oils of both species showed substantial antimicrobial activity against all tested Gram positive bacteria and yeasts. The essential oil of C. pyriformis showed higher cytotoxic activity against tested cell lines than that of C. jambhiri. The IC50 values were 374.36 +/- 43.95 microg/ml and 588.06 +/- 27.12 microg/ml in case of HepG2 cells and 213.87 +/- 18.50 microg/ml and 512.45 +/- 61.46 microg/ml in case of MIA-PaCa-2 cells, respectively.