The levels of, zinc, copper, Fe, Zn, Cu, Mn, Mg, K, Na, and Cl and the activity of carbonic anhydrase were determined in lambs with pneumonia. Asignificant decrease of p < 0.01 level in Zn concentration, in Cu level (p < 0.001) and significant increases in K and Na levels (p < 0.05) and of the Cu/Zn ratio (p < 0.001) were observed in the study group. The carbonic anhydrase activity was decreased in the study group, but the decrease was not statistically significant (p > 0.05). Also, nonsignificant decreases of Fe, Mg, and Cl and increase of the Mn concentration were also observed in the lambs with pneumonia (p > 0.05). Our results suggest that the significant element changes reported here and the Cu/ Zn ratio, but not the activity of carbonic anhydrase, can be used as indicators of pneumococcal infection.