Labour and greenhouse experiments were conducted to study the effect of magnetic field treated water on germination, growth and physiological and biochemical changes in tomato (Lycopersicon esculentum L.), wheat (Triticum aestivum L.) and pea (Pisum sativum L.). The results indicated that magnetic field treated water increased seed germination percentage, seed germination value and seedling vigour index. Magnetic field treated water increased also plant height, leaf area per plant, specific leaf area (SLA), leaf relative water content (LRWC), whereas the leaf water deficit (LWD) values were decreased. Biochemical analysis of the plant leaves irrigated by magnetic field treated water clarified changes in the photosynthetic pigments, UV-absorbing substances (UVAS), activities of peroxidase (POX) and polyphenol oxidase (PPO) enzymes, carbohydrates, phenolics and mineral ion contents. The latter changes are associated with the modifications in the membrane integrity of the plant leaves and the concentrations of some endogenous hormones in the plant shoots.