Temperature-dependent bandwidths and responsivities of uni-traveling-carrier (UTC) and modified uni-traveling-carrier (MUTC) photodiodes were theoretically and experimentally investigated. Theoretical and experimental responsivities of the UTC and MUTC photodiodes were improved as the operating temperature increased. On the other hand, each type of photodiode exhibited different temperature-dependent bandwidth characteristics depending on the thickness of the undoped photoabsorption layer. The bandwidth characteristics of the MUTC photodiode showed weak temperature dependence, which makes it suitable for application to outdoor optoelectronic converters.