By analysing a sample of 158 globular clusters belonging to the galaxy M 31 or Andromeda Nebula (AN) in the framework of a spherically symmetric model with constant circular velocity a value of 260 ± 40 kms−1 for this quantity is obtained. It is also found that the number density of AN globulars roughly decreases as the cube of the distance to the centre with a cutoff radius of about 40 kpc. The implied AN mass within this cutoff is about 0.6 TM⊙ (1 TM⊙ = 1012M⊙). Bearing in mind the model limitations this mass is rather an upper limit. The present results suggest 1.5 as a probable value for the mass ratio of AN to the Milky Way unless their massive dark coronae are significantly different in size.