Differences in the reactions to PHA, Con A and cervical cancer culture cell (OG cell) mitogens between lymphocytes from the peripheral blood and regional lymphnodes were studied in an attempt to examine the cellular immunity of cervical cancer patients. The uptake of (3)H-TdR by peripheral lymphocytes elevated significantly on reaction to PHA and Con A, but the elevated level was lower than that of the normal control group. When using the OG cell mitogen, no reaction was seen. However, when the serum of the cervical cancer patients was added, inhibition of blastogenesis on reaction with OG cell mitogen was evident, although no reaction was seen on reaction with PHA and Con A mitogens. Blastogenesis was seen on reaction of the regional lymphnode lymphocytes with all three of the mitogens. The blastogenesis rate was higher with secondary regional lymphnodes than primary ones. The above results were discussed in relation to the clinical course.