Carbon dioxide concentration, air temperature, and humidity were monitored at (1) two cave sites and (2) three adjacent karst soils. The data over a one-year period are supported by dripwater chemistry and cave visiting frequency. The results indicate that the sources of cave CO2 are anthropogenic and epikarstic ones in addition to ordinary soils. Epikarstic CO2 produced under almost stationary conditions probably control dripwater chemistry and cave’s CO2 maxima. Based on breathing and door opening, anthropogenic activity affects instantaneous cave CO2 levels, depending on site volume/position and visitor number. A conceptual model of the CO2 dynamics of the soil-cave system is proposed. The study indicates that karst processes such as limestone dissolution and speleothem growth need not be entirely/directly controlled by external climatic conditions.