Many studies have revealed correlation between serum or salivary immunoglobulin concentration and the progress of caries. Pathogens residing in the oral cavity can stimulate immune cells to produce cytokines. Antibacterial cellular reaction of T-cells in course of caries is related to the expression of superficial antigens of Streptococcus mutans. Interleukin-1β (IL-1β) – one of the most important cytokines in the human immune system – plays pivotal role in the anti-bacterial defense system. The aim of the presented study was to assess the IL-1β level in saliva, as well as to evaluate the Streptococcus mutans prevalence in the oral cavity. The statistical analysis of results revealed a relevant correlation between salivary IL-1β concentration and Streptococcus mutans level in oral cavity, thus suggesting the IL-1 significance in caries etiopathogenesis or denoting the modulation of cytokine concentration by bacterial antigens.