Background: Arboviruses often cause widespread morbidity in children in endemic regions. Data on the burden of arboviruses in Kenyan children are limited. Objectives: This study was performed to determine the seroprevalence of yellow fever (YFV), dengue (DENV), West Nile (WNV), and chikungunya (CHIKV) viruses among children 1-12 years of age at two health facilities in Teso South Sub-County in Western Kenya. Methods: In a hospital-based cross-sectional survey, a questionnaire was used to collect sociodemographic information. Serum drawn from the children was tested for IgA/IgM/IgG serocomplex antibodies to selected arboviruses using indirect ELISA and plaque reduction neutralization tests. Results: A total of 182 (27.7%) of the 656 participants tested were positive for any arbovirus antibody. Of these, 4.4% (29/656) tested positive for YFV, 9.6% (62/649) for WNV, 5.6% (36/649) for CHIKV, 1.4% (5/368) for DENV1, 9% (59/656) for DENV2, and 19.7% (40/203) for DENV3. Neutralizing antibodies to CHIKV were found in 77.8% (42/54) of participants, to YFV in 15.8% (3/19), to DENV2 in 58% (29/50), and to WNV in 8% (1/55). Sex, age, urban residence, schooling, and lack of vaccination were associated with arbovirus exposure. Conclusions: This study confirmed that children under 12 years of age in Teso South Sub-County are exposed to ongoing arbovirus infections early in life.