The study aimed to investigate the effect of magnetic fields and different nutrient solutions on growth of lettuce plants under hydroponic system. The experiment was carried out in the Laboratory of the Soils and Water Department, Faculty of Agriculture, Al-Azhar University, Assiut, Egypt, during the winter season of 2018. Six treatments were used: three nutrient solutions (mineral - control, organic - compost tea and C.T, and mix of mineral and organic 50:50 v/v) were treated with and without magnetic field, a randomized complete block design in a split-plot design, with three replications. A magnetic treatment device with its magnetic field of approximately 14500 gauss was used to evaluated the growth parameters and nutrient contents. The results showed that the different nutrient solutions with magnetic fields treated had significant increases in all plant parameters. In particular, the mix-nutrient (mineral and organic 50:50 v/v) treated with magnetic fields statistically showed significant increases in all values of growth parameters (plant height, number of leaves/plant, total-chlorophyll, diameter stem and leaf area) and nutrient contents (N, P and K), with mean values of 40.33 cm, 25.00, 41.33 mg\g tissue, 1.49 cm, 13759.33 cm2/plant and 6.03, 0.21 and 1.86%, respectively. This study suggests that the effects of magnetic field treatments act as a protective application of organic nutrition solution in the hydroponic organic system.