Department of Chemistry, Dr. H. S. Gour University, Sagar-470 003, India Manuscript received 16 November 1999, revised 10 August 2001, accepted 20 August 2001 Polarographic technique has been used to determine the stability constants (log β) of CdII complex with glycine, a-alanine, L-valine, L-leucine, L-asparagine and L-glutamine as primary ligands and vitamin B1 (thiamine) as secondary ligand at pH 8.50 ± 0.01 and the ionic strength µ = 1.0 mol dm-3 (KN03). Cd11 forms I : I : I, 1 : I : 2 and 1 : 2: 1 complexes at 25°.