One hundred seven samples of potato tubers and roots were collected from different commercial potato fields of the Southern Brazilian states, Rio Grande do Sul (RS), Santa Catarina (SC), and Paraná (PR) in order to evaluate the occurrence, geographical distribution, and morphological characterization of lesion nematode (Pratylenchus sp.). Pratylenchus brachyurus was detected in 21.5% of the collected potato samples corresponding to 23.94, 21.02, and 13.33% of samples obtained in RS, PR, and SC states, respectively. Subsequently, nine commercial potato cultivars were evaluated for resistance to P. brachyurus in greenhouse at 25°C ± 5°C. Among the genotypes tested, the cultivars 'Bel', 'Eliza', 'Cris', and 'Clara' were immune to P. brachyurus. On the other hand, 'Catucha', 'Ana', 'Cota', and 'Agata' cultivars were resistant, and 'Asterix' behaved as susceptible to this lesion nematode species.