This study was undertaken to observe the relationship between salivary IgA, IgG, agglutinin titer & dental caries. The subjects divided into two groups, an active caries group (AC group) and caries-free and treated caries group (CFTC group). The AC group consisted of 36 subjects who had one or more carious lesions and the CFTC group of 12 subjects who had no evidence of caries or had filled teeth without present carious teeth for the last six months. The IgA, IgG and IgM levels in their saliva were measured by single radial immunodiffusion method using a disposable low-level immunodiffusion plate. The salivary agglutinin titers to Streptococcus mutans were measured by microtitration system. The results were as follow; 1. The mean value of IgA concentration in saliva of AC group was slightly higher than that of CFTC group, but its difference was slight. 2. The mean value of IgG concentration in saliva of AC group was slightly lower than that of CFTC group. The IgM concentration in saliva of both groups was neither below 1.1 mg/dl nor detected on LC partigen immunodiffusion plate. 3. There was no difference in the agglutinin titer to S. mutans antigen by serotypes, but low level agglutinin to type d was measured in both groups. 4. AC group showed low correlation between IgA, IgG & DMFT, but CFTC group revealed negative correlation. 5. The relationship between salivary IgA & agglutinin titers to S. mutans was low correlation in AC group, but CFTC group showed significant positive correlation. (P<0.05) 6. There were no specific correlations among the concentrations of salivary immunoglobulins, agglutinin titers to S. mutans, and the DMF teeth. They had no close concern to induce the dental caries.