Polar Mesospheric Summer Echoes (PMSE) have been observed at various frequencies from MF to UHF and at various latitudes. Here, we report the observation of PMSE over Svalbard (79 ¿N) at 500 MHz. Although PMSE have been reported earlier at such high latitude at VHF (notably around 50 MHz), they had hitherto not been reported at such high frequency as 500 MHz. Furthermore, this observation represents the first one using a frequency between 224 MHz and 933 MHz. The PMSE scattering mechanism is still open to debate and is certainly frequency dependent: the new observations at 500 MHz will help to identify the transition frequency between different mechanisms. ¿ 2001 American Geophysical Union