Begomovirus infection was suspected in tomato plants exhibiting symptoms of curling and deformation of leaves observed in a survey conducted in northern and central Peru. Rolling circle amplification and restriction fragment length polymorphism analyses suggested that a begomovirus was present in symptomatic plants. The full-length sequence of a begomovirus DNA component was determined, comprising 2591 nucleotides. Based on its genome organization, we suggest it corresponds to the DNA-A of a New World begomovirus. Less than 89% nucleotide sequence identity to known begomoviruses was found, indicating that it corresponds to an isolate of a distinct begomovirus species for which the name tomato leaf deformation virus (ToLDeV) is proposed. Different stretches of the genomic component have the highest sequence identity with different viruses compatible with a recombinant origin. Sequence segments shared common ancestors with isolates of either soybean blistering mosaic virus, tomato yellow spot virus, or tomato chino La Paz virus. Partial sequence analysis of begomovirus isolates present in symptomatic tomato samples collected in northern and central Peru suggested widespread occurrence of this new begomovirus. This is the first confirmation of a begomovirus infection in tomatoes in Peru. © 2010 KNPV.