The levels of salivary Streptococcus mutans and lactobacilli and caries experience were studied in 113 teenagers and 163 adults. The study population consisted of 82 mother-child and 73 father-child pairs. The number of decayed, missing, and filled tooth surfaces (DMFS) was eightfold higher in adults than in teenagers (56.4 ± 22.8 vs. 7.3 ± 6.7). The percentage distribution of the level of salivary S. mutans and lactobacilli was approximately the same in both groups. The mean number of DMFS increased with increasing levels of salivary S. mutans and lactobacilli, the correlation being highly significant both in teenagers and adults. There was a significant correlation of the DMFS indices in the mother-child pairs (r = 0.364), but the correlation was not significant in the father-child pairs (r = 0.138). The salivary level of S. mutans was higher in the children of mothers with high DMFS values compared to the children of mothers with low DMFS value