Magnesium diboride is a promising superconducting material with interesting electrical and mechanical properties. Reactive liquid magnesium infiltration is an effective technology to produce cheap and reliable bulk components potentially suitable for application in electric machinery. This study deals with the magnetic flux-trapping capabilities of bulk samples manufactured through this technique. The aim of this work is to evaluate the samples as magnets for synchronous machines. In this paper, a number of trapped flux measurements on different magnesium diboride samples are reported. The experimental results are discussed on the basis of the numerical model of the superconducting material.