Abstract CR-39 track detectors have been used to measure mean ranges and energy-loss of 17.7 MeV amu -1 86Kr in aluminium, and 16.34 MeV amu -1 238U in Hostaphan. The nuclear track technique employed in this work has been described in brief. The accuracy of measurement has been evaluated and is presented in this paper. Experimental range data are compared with theoretical values obtained from four different sources. The significance and scope of the work is discussed.