Order αs2 perturbative QCD corrections to the Gottfried sum rule

The order αs2 perturbative QCD correction to the Gottfried sum rule is obtained. The result is based on numerical calculation of the order αs2 contribution to the coefficient function and on the new estimate of the three-loop anomalous dimension term. The correction found is negative and rather small. Therefore it does not affect the necessity to introduce flavour-asymmetry between ū and d̄ antiquarks for the description of NMC result for the Gottfried sum rule.