Objective: To document the clinical, laboratory, and epidemiologic characteristics of pediatric patients with murine typhus. Design: Pediatric patients were diagnosed using serologic testing, and clinical, laboratory, and epidemiologic data were retrospectively reviewed. Setting: Of 97 patients, 77 (79%) were identified and treated as inpatients and 20 (21%) were treated as outpatients; most resided in south Texas. Patients: Between 1979 and 1996, medical records and patient-physician interviews were available for 97 patients aged 16 years and younger with murine typhus. Main Outcome Measures: The frequency of clinical symptoms and signs, abnormal laboratory findings, epidemiologic findings, and measures of disease severity were determined. Results: The clinical triad of fever, headache, and rash occurred in only 43 (49%) of 87 pediatric patients throughout the illness. Musculoskeletal symptoms were experienced by 43%, of patients, whereas gastrointestinal tract symptoms (nausea, vomiting, anorexia, and diarrhea) occurred in 77%. Systemic involvement was evident by the frequent occurrence of abnormal laboratory findings referable to multiple organ systems, including the liver, kidney, blood, and central nervous system. Conclusions: Pediatric infection by Rickettsia typhi usually causes mild to moderate systemic illness, In children, the median duration of illness was 12 days (range, 5-29 days), but severe complications were rare. Length of illness was significantly related to the initial diagnosis, whereas the interval to defervescence was related to therapy with a tetracycline or chloramphenicol. Early recognition and treatment is important to prevent prolonged morbidity.