Interaction of the biologically active ligand 3,3-dimethylglutarimide with a series of metal ions has been investigated by a potentiometric method. Acid dissociation constants of the ligand (L) and stability constants for the formation of 1:l (metal to ligand) complexes with Cu(II), Ni(II), Zn(II), Hg(II), Be(I1) and Ag(1) have been determined in aqueous solution at 25.0'C and 0.1 M (KNO,) ionic strength. It has been shown that silver(1) and mercury(I1) ions form two types of complexes, ML and ML, in a stepwise manner. It suggested that in the ML, complex (where M = Ag, Hg), a linear N-M-N bond is formed through the two deprotonated nitrogen atoms of glutarimide rings.