We report the first detection of CO in M 31 ’ s bulge .
The ^ { 12 } CO ( 1-0 ) and ( 2-1 ) lines are both detected in the dust complex D395A/393/384 , at 1 \aas@@fstack { \prime } 3 ( \sim 0.35 kpc ) from the centre .
From these data and from visual extinction data , we derive a CO-luminosity to reddening ratio ( and a CO-luminosity to H _ { 2 } column density ratio ) quite similar to that observed in the local Galactic clouds .
The ( 2-1 ) to ( 1-0 ) line intensity ratio points to a CO rotational temperature and a gas kinetic temperature > 10 K. The molecular mass of the complex , inside a 25 \arcsec ( 100 pc ) region , is 1.5 10 ^ { 4 } M _ { \odot } .