Pseudomonas spp. isolates were collected from tomato plants showing symptoms of pith necrosis during the 2017 and 2018 seasons in the Salto Department, northwest Uruguay. According to physiological, biochemical tests and multilocus phylogenetic analysis (gyrB, rpoD, and rpoB), 25 were characterized as P. mediterranea, five as P. viridiflava, three as P. corrugata, and one as P. marginalis. All of them produced necrotic lesions and pith hollowing in re-inoculated tomato plants. Some P. mediterranea isolates (UYT92018, UYT122018, UYT192018, UYT222018, and UYT372018 from season 2018) did not develop a hypersensitive response (HR) in tobacco like the other P. mediterranea, P. corrugata, P. viridiflava, and P. marginalis isolates. According to our knowledge, this is the first documented report of P. viridiflava and P. marginalis causing tomato pith necrosis in Uruguay. As well as the presence of several Pseudomonas spp. causing tomato pith necrosis in the Salto area P. mediterranea was confirmed to be the most prevalent. © 2023, Koninklijke Nederlandse Planteziektenkundige Vereniging.