An optical data recording medium provided with a recording layer, the recording medium having excellent durability to light and heat, superior writing sensitivity and a high C/N value, wherein at least one a group of anion selected from a group of hexafluorophosphate ion (PF.sub.6 .sup.-), trifluoromethane sulfonate ion (CF.sub.3 SO.sub.3 .sup.-) or thiocyanate ion (SCN.sup.-) is present as the anion in an indol cyanine dye having a methyne chain present in the recording layer of the optical data recording medium.