The evaluation of the heavy metal discharge from liming materials into the arable soil in NW Croatia is based upon the contents of Fe, Mn, Pb, Cu, Zn, Cd, Co and Hg in the studied carbonate raw materials, obtained under simulated conditions of the lowest presumed acidity (pH>3) which can occur in the agroecological environment. From the agroecological viewpoint, the heavy metal contents of the analyzed liming materials are much lower than the permissible levels. Only cadmium contents indicate that a certain amount of care should be taken into account. Because cadmium is bound in labile forms (pH>3 soluble fraction), it has to be considered quite mobile and biologically available in limed arable soils that are affected by drastic pH changes in the agroecological environment