In the title compound, [Mo(C(37)H(53)N(3))(CO)(3)], the Mo atom to ring-centroid distance in the η(6)-coordinated tricarbonyl-molybdenum group is 1.958 (1) Å. The three C O groups are pseudo-octa-hedrally disposed with C-Mo-C angles ranging from 80.7 (1) to 87.4 (1)°. The two uncoordinated 2,6-diisopropyl-phenyl-substituted benzene rings form dihedral angles of 75.96 (8) and 78.01 (9)° with the mean plane of the guanidine group. The coordinated benzene ring is in a slight sofa conformation with the N-substituted C atom and the bonded N atom dispaced by 0.090 (3) and 0.458 (4) Å, respectively, from the mean plane of the remaining ring atoms. In the crystal, despite there being two N-H donor groups, no conventional hydrogen bonds are present. This may be because of the steric effects of the bulky diisopropyl-phenyl groups.