Dilatometric measurements were obtained on Vanadium Permendur in view of its reported instability above 500C. Contrary to the results of other investigators, heating a specimen initially in the ordered condition to 850C and cooling to room temperature did not show a permanent change in length. However, heating to 1000C or above, just into the austenite field, and cooling to room temperature resulted in a peimanent decrease in length of about6×10−4 cm./cm. Each of several subsequent cycles resulted in an additional decrease in length. In addition to this change, the dilatometric curves showed other discontinuities. As expected the order‐disorder transformation occurred at 700C. The curves also showed a maximum and minimum slope at about 490C and 540C respectively. The reason for these changes in the slope remains to be determined.