NOWADAYS, there is a great demand concerning searching about renewable energy sources. Therefore, wild plants such as Tamarix nilotica and Pluchea dioscoridis could be used as fossil fuel-alternative to meet the huge increments in the energy demand. The aerial parts of T. nilotica were collected from the Cairo–Suez road, while those of P. dioscoridis were collected from Wadi Hagul, Egypt. The biofuel generating compounds including lipids, carbohydrates, cellulose, pectin and lignin were assayed. The physico-chemical properties of the produced biodiesel were calculated. The obtained results indicated that, the high cellulose content (25.02%) of T. nilotica increases its potentiality for bioethanol production. The GC-MS analysis showed that P. dioscoridis displayed the highest levels of saturated fatty acid (SFAs) and a desirable degree of unsaturation (DU). The biodiesel properties in terms of iodine value (IV), saponification number (SN), cetane number (CN), oxidative stability (OS), high heating value (HHV), kinematic viscosity (η) and density (ρ) for both species were within the recommended standards and mostly met the criteria required to be a diesel substitute compared with the international biodiesel standards. Particularly biodiesel produced from P. dioscoridis has good and suitable engine parameters (SN 196.3, IV 76.81 and CN 114.18).