Rickettsia felis has been reported to be a cause of fever in sub-Saharan Africa, but this association has been poorly evaluated in Gabon. We assessed the prevalence of this bacterium among children <15 years of age in 4 areas of Gabon; the locations were in urban, semiurban, and rural areas. DNA samples from 410 febrile children and 60 afe-brile children were analyzed by quantitative PCR. Overall, the prevalence of R. felis among febrile and afebrile children was 10.2% (42/410 children) and 3.3% (2/60 children), respectively. Prevalence differed among febrile children living in areas that are urban (Franceville, 1.3% [1/77]), semiur-ban (Koulamoutou, 2.1% [3/141]), and rural (Lastourville, 11.2% [15/134]; Fougamou, 39.7% [23/58]). Furthermore, in a rural area (Fougamou), R. felis was significantly more prevalent in febrile (39.7% [23/58]) than afebrile children (5.0% [1/20]). Additional studies are needed to better understand the pathogenic role of R. felis in this part of the world. O ver the past decade, reported cases of malaria and associated deaths have declined in Africa (1). This decrease has led to a search for other causes of fever in Africa, where unexplained febrile illnesses are one of the major health problems. In some sub-Saharan Africa countries, malaria treatments are still administered without a biolog-ic diagnosis. For example, an assessment of complicated malaria and other severe febrile illness cases in a pediatric ward in Libreville, Gabon, showed that 43.5% of the children who received an antimalarial treatment had micros-copy test results negative for malaria (2). Other studies have shown that, in addition to malaria, other bacterial infections are a major cause of fever in Africa (3–6). Staphylococcus aureus, Streptococcus pneumoniae, nontyphoidal Salmonella spp., Klebsiella pneumoniae, and Escherichia coli are the bacteria most often detected in sub-Saharan Africa by the culture method (7,8). The use of molecular tools has enabled the identification of the following fastidious bacteria as a cause of unexplained fevers in Africa: Rickettsia spp., including R. felis (3–5,9); Coxi-ella burnetii (10); Tropheryma whipplei (11); and Borrelia spp. (12,13). However, the epidemiology of many fastidious bacteria, such as R. felis, remains poorly understood. In rural areas of Senegal, the prevalence of R. felis was generally higher (7%–24%) than that in urban areas of sub-Saharan African, such as Franceville, Gabon (10%) (14). R. felis is a gram-negative bacterium belonging to the spotted fever group of Rickettsia spp. In Gabon, the bacterium has been reported in arthropods, including Ctenocephal-ides felis cat fleas (15) and Aedes albopictus mosquitoes (16), and in humans (14). Similar to many African countries , Gabon has a strong disparity between health care in urban and rural areas; in rural areas, little is known about the epidemiology of infectious diseases. The aim of our study was to evaluate the prevalence of R. felis infection among febrile and afebrile children in rural and urban areas of Ga-bon and the possible role of R. felis in acute febrile illness.