In two independent Irish potato experiments carried out at the Lameira Exp. Sta. of the Instituto Agronômico de Campinas, in 1952, serious damage was observed in the tubers due to the attack of a Diplopoda - Pseudonannolenidae, Pseudonannolene paulista Brölemann, 1902. One of these experiments was undertaken in order to test the varieties Konsuragis and Eigenheimer imported from Sweden. Amonium sulphate, cotton or ricinus meal were used as source of Nitrogen at the rate of 80 kg of N per hectare. Superphosphate at the rate of 120 kg of P2O5 and Potassium sulphate at the rate of 60 kg of K2O were also used in this experiment. It has been observed that the number of affected tubers was greater in the Konsuragis variety and also that the attack by Diplópoda was more intensive in the plots where cotton or ricinus meal was used. In the other experiment the following varieties were tested, all them received from Holland: Bintje, Eersteling, Saskia, Gineke, Eigeriheimer, Voran and Alpha. Only Amonium sulphate was used as source of nitrogen, this element, P2O5, and K2O, having been added at the same rate as in the first experiment. The varieties Bintje, Eersteling and Saskia had a great number of damaged tubers while Alpha seemed to be much more resistent. The maximum temperature observed during the experiment varied from 21.3 to 30.2°C and the minimum temperature from 5.5 to 14.2°C. The amount of rainfall was very small, only 16 mm being registered during February to May. Chemical analysis of the soil revealed that it was poor in mineral contents and had high acidity. The present observation confirms the findings of Blunck, who established that when the soil is hot and dry, Diplópoda feeds on potato tubers in order to get water. It has been suggested that the attack by the Diplópoda here observed is of the same nature as that caused by the Diplópoda Cylindroiulus frisius Verhoeff and C. teutonicus Poc. observed in Germany in tubers of Irish potato.