Dynamics of onion seeds germination with different germinability and magnetic field influence with variable intensity on onion germinative activity was determined in trials. Amika F1 hybrid marked low germinative activity. On 21th day after trial foundation it reached germinability of 34–46%. Halftime of this germination was reached on fourth to fifth day after trial foundation. Exhibition variety had convenient germination activity, 70–91%. Halftime of its germinability was reached on sixth to eighth day after trial foundation. On the base of submitted results there can be said that the seed with low germinative activity has faster initial start of germination. The seed with suitable germinative activity has more regular course of germinability from the beginning till the end of germination. Seeds of varieties Amika F1 and Exhibition achieved significantly lower germination in the radiation intensity of 20 mT compared to other variants with the radiation intensity of 40 mT, 55 mT and the control one. Between the variants of 40 mT, 55 mT and the control one the differences were not significant.