For the first time electrons on liquid helium have been subjected to magnetic fields as high as 22 T. The magnetoconductance has been measured in the temperature range 1.5–2 K, where the mobility of the electrons is dominated by the scattering with helium vapor atoms. Since helium is a diamagnetic liquid, the presence of field gradients has to be taken into account in high magnetic fields. The conductance data inherently contain the effect of the field-induced deformation of the helium surface. An estimation of this effect is presented. The corrected data are discussed within quantum transport theory.