目的：探讨儿童不明原因发热(FUO)的病因，诊断方法和思维方式。方法：回顾性地总结分析1996年1月至2000年12月符合FUO诊断标准的住院患儿317例。结果：317例中明确诊断有298例，确诊率为94.0%。感染性疾病160例(53.7%)，非感染性疾病138例(46.3%)，两者之比为1.15∶1。最终确定诊断的方法分别为：临床综合诊断140例(47.0%)；血清和骨髓细菌培养检查64例(21.5%)；组织活检37例(12.4%)；影像学检查35例(11.7%)；尸体解剖11例(3.7%)；骨髓形态学确诊6例(1.9%)；回顾性诊断5例(1.7%)。结论：根据临床经过和必要的实验室检查大部分FUO病例可以明确病因诊断，病理学检查对疑难病例的诊断提供重要依据，极少数病人最终只能依赖尸检明确诊断。感染性疾病、结缔组织病和恶性肿瘤性疾病是该组FUO的主要原因。

OBJECTIVE: To review the etiology of fever of unknown origin (FUO) and the methods used to establish a diagnosis. METHODS: A retrospective review of the medical records of 317 patients with FUO admitted between January, 1996 and December, 2000 was performed. RESULTS: Of the 317 children, 298 cases (94.0%) had a definitive etiology established. Of the 298 cases, 160 (53.7%) had infectious diseases and non infectious diseases, such as collagen vascular disease, and neoplasm which accounted for a large fraction of the remainder. A diagnosis was established in 140 (47.0%) by comprehensive clinical analysis alone. Culture of bacteria in serum and biopsy specimens established a diagnosis in 64 cases (21.5%) and 37 cases (12.4%), respectively. Noninvasive imaging techniques (35 cases; 11.7%), autopsy (11 cases; 3.7%), bone marrow examination (6 cases; 1.9%) and retrospective diagnosis (5 cases; 1.7%) accounted for the remainder of the diagnosis. CONCLUSIONS: Most cases of FUO can be diagnosed by clinical characteristics of the patients and by essential laboratory studies. Pathological examination is very important in diagnosing the etiology of FUO. Infectious diseases, collagen vascular disease and neoplasm are the major causes of FUO in children.