The impact of electromagnetic fields of the power of 1800 Am-1 (=H), 1000 Am-1 (=H), 800 Am-1 (~H), 1500 Am-1 (~H), 200 Am-1 (~H) on the morphological and physiological parameters of tomato plants which were affected directly during the whole vegetation by these fields, and in the first and second generation after effect, was studied in vegetation trials in the glass greenhouses of the phytotron complex. When tomatoes were affected with electromagnetic fields directly during the whole vegetation period, seedlings developed rapidly, and formed the biggest leaf area and grew up the highest when affected by the electromagnetic field of 1500 Am-1 (~H). The leaves of tomatoes affected by electromagnetic fields of 1000 Am-1 (=H) and 1500 Am-1 (~H) accumulated the highest content of pigments. The most intensive photosynthesis occurred under the effect of electromagnetic fields of 1800 Am-1 (=H) and 1500 Am-1 (~H). Electromagnetic field of 200 Am-1 (~H) mostly impeded the formation of pigments and decreased the yield. The greater negative effect of electromagnetic fields was established for germination energy of seeds chosen from tomatoes which were affected directly during the whole vegetation period. The effect of electromagnetic field of the power of 1000 Am-1 (=H) and 200 Am-1 (~H) was distinguished most notably.