During a study of the 'tunta' (frozen-dry potato) production process in Peru, a bacterial strain, LMT03(T), was isolated from the straw grass in which the potatoes are dried. This strain was classified into the genus Pseudomonas on the basis of the 16S rRNA gene sequence analysis, and is most closely related to Pseudomonas argentinensis CH01(T) with 99.3 % identity in this gene and 96 %, 92 % and 86 % identities in rpoB, rpoD and gyrB genes, respectively. Strain LMT03(T) has a single polar flagellum, like other related yellow-pigment-producing pseudomonads. The major quinone is Q-9. The major fatty acids are C18 : 1ω7c in summed feature 8 (40.82 %), C16 : 1ω6c/C16 : 1ω6c in summed feature 3 (23.72 %) and C16 : 0 (15.20 %). The strain produces oxidase but it does not produce gelatinase, indole, urease, arginine dihydrolase or β-galactosidase. Catalase production was very weak after 28 and 48 h incubation on nutrient agar medium. Nitrate reduction is negative. It does not hydrolyse aesculin. The DNA G+C content is 57.8 mol%. DNA-DNA hybridization results showed lower than 52 % relatedness with respect to the type strain of P. argentinensis, CH01(T). These results, together with other phenotypic characteristics, support the definition of a novel species within the genus Pseudomonas, for which the name Pseudomonas punonensis sp. nov. is proposed. The type strain is LMT03(T) ( = LMG 26839(T) = CECT 8089(T)).