The distribution of prompt neutron numbers (Pv) in the spontaneous fission of uranium-238 was measured using a cadmium-loaded liquid scintillation detector. The experimental results show, that σv, the width of Pv distribution, is equal to 0.90± 0.09, wbich is smaller them the corresponding values of other even-even heavy nuclei (Pu, Cm, Cf and Fm). It was found also, that the average neutron number v= 1.96 ± 0.05, which is in agreement with previous results.