The influence of the vibrational motion on the magnetic hyperfine coupling constants (hfcc’s) in the X(3) Sigma(g)(-) of B2H2 is investigated by means of ab initio methods. The present study clearly shows that for the isotropic hfcc’s of the boron centers the incorporation of the vibrational effects is essential already for the vibrational ground state. For the boron center the isotropic hfcc’s calculated for the lowest vibrational state (A(iso)(B-11) = -5.2 MHz) differ considerably from the value obtained at the equilibrium geometry (A(iso)(B-11) = -14.0 MHz) but agrees excellently with the experimental value (A(iso)(B-11) = -5.2 MHz) obtained previously. For the hydrogen centers and for all anisotropic hfcc’s the effects are found to be much smaller. In the present study the averaged values for various vibrational states and isotopic effects are given.