Abstract: Effects of the root endophytic fungus (Piriformospora indica) on growth and some physiological aspects such as pigments of photosynthesis, proline content, peroxidase enzyme and mineral acquisition of fenugreek (Trigonella foenum-graecum) plants under different levels of salinity (0, 50, 100, 150 and 200 mM NaCl) were studied. Based on the results, Piriformospora indica plays an important role in promoting and alleviating the fenugreek plant against the stress of salinity on both roots and stems (lengths and weights). The fungus stimulated the root lengths (0% - 35.58%), root weights (2.08% - 33%), stem lengths (1.2% - 34.28%) and stem weights (34.09% - 106.31%). Concerning the pigments of photosynthesis (chlorophyll a & b and carotenoids) of fenugreek (non-inoculated and inoculated plants), it is clear thatthe three pigments tested were faintly decreased in both control and the lowest concentrations of NaCl (-4.01%, -5.51% & -2.88% and -8.24%, -8.50% & 6.50%, respectively). Whereas, P. indica stimulated the biosynthesis of pigments at highest concentrations (14.58% - 38.83%, 12.64% - 84.32% and 0.49% - 43.33% of the three pigments, respectively). The fungus increased the content of proline in control (5.73%) and treated plants with NaCl (4 doses) with inoculation compared with un-inoculated plants (5.87- 9.45%). Regarding the antioxidant enzyme (peroxidase), the fungus stimulated the enzyme activity in both control by 8.55% and in three concentrations of NaCl (50, 150&200 mM NaCl) by 106.51%, 186.72% and 166.22%, respectively. P. indica stimulated the uptake of the mono-equivalent (Na+& K+, 106.6% & 1.33%, respectively) with a sharp decrease in the bi-equivalent (Mg++,-70.28%). The fungus had high uptake of the three metals, followed by negative uptake at 100 mM NaCl. Of the highest doses (150 & 200 mM NaCl). Also, the fungus stimulated the absorption of K+ ions (32.61% & 31.53%) and Mg++ ions (24.04% & 24.44%) with decrease Na+ ions (-58.32% & -21.42). Keywords: Piriformospora indica, fungi, salinity, fenugreek, growth, photosynthesis, proline, peroxidase, minerals.