This is the first description of the complete genome sequence of a new monopartite begomovirus isolated from tomato leaves with symptoms of tomato (yellow) leaf curl disease collected on Reunion Island, for which we propose the name "tomato yellow leaf curl Reunion virus" (TYLCREV). Phylogenetic analysis showed that TYLCREV belongs to the Old World monopartite begomoviruses and is most closely related to tomato yellow leaf curl virus (TYLCV). The genome of TYLCREV displays evidence of interspecies recombination and is composed of a portion (52%) that is closely related to TYLCV (>97.6% sequence identity) and a portion (48%) that is closely related to begomoviruses that have been found in tomato plants in Madagascar (> 91.6% sequence identity). The discovery of TYLCREV in diseased tomato plants in Reunion calls for epidemiological surveillance and further investigations to assess the prevalence and risks associated to this new virus in Reunion and beyond.