BACKGROUND Intracranial hemorrhage (ICH) in full-term infants is uncommon and is a rare cause of neonatal fever. This study was conducted to estimate the incidences of ICH and fever in a hospital-based population, and to determine if the clinical features of neonatal ICH with and without hyperthermia differ. METHODS We selected 315 afebrile neonates who received cranial ultrasonography screening from 2003 to 2004 as the control group, and 153 neonates diagnosed with fever from 1998 to 2004 as the study group. During the same period, 28 full-term neonates with birth weights >2500g and ICH in the first week of life were enrolled retrospectively. They were divided into hyperthermia (n=11) and nonhyperthermia (n=17) groups. RESULTS Three babies in the control group and 11 in the study group had ICH; the incidence of ICH in the hyperthermia group was significantly higher (3/315 vs. 11/153; p < 0.001). Compared with the nonhyperthermia group, the hyperthermia group had Less cyanosis (2/11 vs. 10/17; p = 0.04), Less lymphocyte predominance (33.7 vs. 80%; p = 0.032), higher neutrophil/lymphocyte ratio (1.9 vs. 0.3; p = 0.006), higher erythrocyte/leukocyte ratio (425 vs. 79.5; p = 0.05) in cerebrospinal fluid and an increased incidence of subarachnoid hemorrhage accompanied by intracerebral parenchymal hemorrhage (4/11 vs. 0/17; p = 0.016). CONCLUSIONS The incidence of ICH was higher in febrile than in afebrile neonates. ICH presenting with hyperthermia might go unrecognized, because its other symptoms are subtle and a neutrophil predominance in the cerebrospinal fluid might result in a misdiagnosis of meningitis. ICH in the interior brain tended to manifest more commonly as hyperthermia than did ICH in the superficial brain. A cranial image examination should be considered in the evaluation of neonatal fever.