ABSTRACT: Statistic concerning hydraulic data on transmissivity coefficient (T; in m2•s-1) and hydraulic conductivity (k; in m•s-1) was performed for andesites, rhyolites and basalts and related volcanoclastic rocks located in the Central-Slovakian Neogene Volcanic Field. A total of 529 hydrodynamically tested boreholes was extracted and evaluated by processing the drawdown and respective yield to give the pumped discharge in the first metre of drawdown (standard specific yield). Hydraulic parameters were estimated for the 13 lithologically different types of effusive and volcanoclastic rocks. The highest values were obtained for andesites and related volcanoclastic rocks. The mean transmissivity value for volcanoclastic rocks (T = 3.5•10-4 m2•s-1) is just slightly higher than the value estimated for andesites (T = 2.5•10-4 m2•s-1). Rhyolites (T = 9.2•10-5 m2•s-1) and related volcanoclastic rocks (T = 7.7•10-5 m2•s-1) show the lowest obtained mean value for the transmissivity coefficient. Mean hydraulic conductivity of andesites showed slightly higher values (k = 5.3•10-6 m•s-1) than of rhyolites (k = 4.7•10-6 m•s-1) and slightly lower values than basalts (k = 7.8•10-6 m•s-1). Volcanoclastic rocks do not show any overall substantially different mean values of hydraulic conductivity (k = 9.9•10-6 m•s-1) than lava aquifers of all types (k = 5.3•10-6 m•s-1).