In this paper, a review of experiments related to liquid metal heat transfer under mixed convection is performed. This study is relevant because heat transfer during start-up and shut-down procedures, and operational transients is influenced by natural convection, resulting in mixed convection, which differs considerably from forced convection. Up to now, simulation tools like TRACE, RELAP, etc. apply only forced convection models for liquid metal heat transfer. The influence of mixed convection on the heat transfer during the above mentioned transients is completely ignored. Hence, it is not possible to simulate mixed convection with best-estimate system codes like TRACE or RELAP. In order to perform realistic simulations of plants and experimental facilities mixed convection must be addressed and considered. Therefore, the literature is reviewed for experimental data with liquid metal heat transfer under mixed convection and generally applicable statements and models will be provided. A clear distinction in the heat transfer behavior for low and high Péclet number flows can be identified. Thereby, a Péclet number dependency is visible for higher Péclet numbers (Pe > 100). Furthermore, the heat transfer (Nusselt number) cannot be presented as a function of one dimensionless parameter. To identify underlying phenomena, especially when comparing different experimental scenarios several dimensionless numbers are needed (Gr*, B, Z, etc.). Based on this study, it is possible to derive a model for the heat transfer under mixed convection. Nevertheless, these findings and the sparse number of experiments also indicate the need for new and comprehensive experiments.