Results on the creation and properties of transistor-type MIS structures (MIST) with an Al2O3 thin-film gate dielectric based on PbSnTe : In films obtained by molecular beam epitaxy are presented. The source-drain current-voltage characteristics (CVC) and gate-controlled characteristics of the MIST at [BT=4.2 K have been investigated. It is shown that in MIST based on PbSnTe : In films with n~1017 cm-3 the modulation of the channel current reaches 7-8% in the range of gate voltages -10 V<Ugate<+10 V. The features of the source-drain CVC and the gate-controlled characteristics for a pulsed and sawtooth variation of Ugate are considered. Keywords: solid solution PbSnTe : In, field effect, MIS structure, Al2O3.