Serum C Reactive Protein (CRP) levels were measured in 36 neonates with a suspicion of sepsis. In the 11 children in whom septicemia was proven, CRP levels were abnormal in all cases, while hematologic data were significantly changed in 3 cases only (27%). In the 16 neonates who were not infected, CRP was abnormal in only one case, and hematologic data significantly changed in 2 (12%). In 9 neonates with at least 2 peripheral samples positive for the same organism, CRP and hematologic data were respectively abnormal in 6 (66%) and one (11%) cases.