α-Ureidoalkylation of N-[2-(dimethylamino)ethyl]urea with 1,3-unsubstituted, 1,3-dialkyl-, and 1,3-dimethyl-4,5-diphenyl-4,5-dihydroxyimidazolidin-2-ones(thiones) was systematically studied. Hitherto unknown N-[2-(dimethylamino)ethyl]glycolurils and their hydrochlorides were synthesized. The yields of the target glycoluril hydrochlorides decreased on going from 1,3-H2- to 1,3-dialkyl-4,5-dihydroxyimidazolidin-2-ones and increased with the introduction of phenyl groups at the positions 4 and 5 of the starting 4,5-dihydroxyimidazolidin-2-one. X-ray diffraction study showed that 2-[2-(dimethylamino)ethyl]glycoluril crystallizes in the form of a conglomerate.