Low temperature specific heat data of aligned single crystals of UPt3, RRR = 140, with high magnetic field applied either along the c-axis or perpendicular to the c-axis are reported. No evidence for a metamagnetic transition as observed previously in susceptibility and resistivity measurements is seen, with no change for H in the c-direction and large ( ≈ 20%), temperature-dependent changes observed for H perpendicular to c. Magnetoresistivity measurements on one of the single crystals indicate that the transition in resistivity occurs at a lower field in our sample than observed in the sample reported on previously (18 vs. 20 T). © 1988.