We measured circular dichroism spectra to examine the complex-formation capability of various kinds of polysaccharides with poly(C). The results show that schizophyllan and lentinan can interact with poly(C), on the other hand, amylose, pullulan, dextran, and curdlan cannot. This difference clearly indicates that the water soluble beta -1,3-glucan can bind with polynucleotides. The molecular weight dependence of the complex formation has established that at least 30 glucose sequence length is necessary to incorporate the most bases into the complex.