Salinity is one of the most important problems in Egypt. Soil salinity decreases growth, photosynthetic activity, and results in nutrient imbalance in plants. This study evaluated the efficacy of the foliar applied Spirulina platensis (100mg/L) in reducing salinity effects in Vicia faba L. plants. The treatments are, T1 (control), T2 (salinity, 135mM from NaCl, equivalent to 13dS m−1), T3 (Spirulina platensis, 100mg/L), and T4 (salinity, 135mM+ Spirulina platensis, 100mg/L). Salinity decreased significantly chlorophyll a+b, carotenoids, weights of 100 seed, photosynthetic activity (14CO2 fixation), transpiration rate , total protein and (N, P and K). Application of T4 improved the above parameters as compared to salt-stressed plants. Salinity increased significantly the SOD, POD, CAT, GPX, MDA, free proline, total phenol and Na+ and
Cl− as compared to the control plants. However, T4 treatment decreased the activity of the above parameters as compared to salt-stressed plants. Foliar applied Spirulina platensis ameliorated adverse effects of salinity by enhancing total protein level, N, P and K and photosynthetic activity (14CO2 assimilation). This first attempt to evaluate the potential of Spirulina platensis as growth enhancer under salt-stressed Vicia faba indicated that exogenously applied Spirulina platensis (100mg/L) provided more benefit against salinity stress.