Pneumococcal serotyping by quellung reaction has been performed in five Italian areas on 267 strains, isolated from throat swab, sputum, blood, liquor, etc. 37 serotypes have been identified. The most frequent types resulted 19, 6, 3, 20, 9, 4 (in 50% of total samples), with no difference from those detected in other European countries. The proportion of type 19 was the highest among all age group, in four out of five different areas and in bacteremic pneumonia and meningitis. 36 strains were isolated from infection sites among which type 19 resulted more frequent than in isolates from throat swab and sputum (27.7% versus 16.1%). Pneumococcal serotyping should be routinely done in the light of forthcoming use of polysaccharide vaccine.