Most ureilite meteorites contain diamonds that are generally thought to have been formed by shock-induced high pressure that converted carbonaceous material to diamond. We measured Raman spectra of ureilite diamond in order to investigate the origin of such diamonds. The FWHM (full width at half maximum) of the Raman line at 1330 cm-1 from diamond in the ALH-77257 ureilite is about 10 cm-1 which is narrower than those of artificially shock-produced diamonds (>20 cm-1) but within the range of vapor-growth diamonds measured previously. This result suggests that the vapor-growth origin of ureilite diamond in an interstellar environment should be considered seriously, although further studies are necessary to characterize vapor-growth diamonds by measuring the Raman line of diamonds synthesized by various methods. ¿ American Geophysical Union 1988