The effect of three planting dates (August 25, September and October) on infectivity of root- knot nematode species and productivity of sugar beet var. Pleno was evaluated. The results indicated that the 1^st planting date showed the highest values of nematode infection parameters (i.e. numbers of galls, eggmasses, development stages root system^-1, juveniles in soil and final population as well as reproduction factor) followed by 2^nd planting date. However, the 3^rd planting date achieved the lowest values of those nematode parameters. In addition, the data revealed that the 1^st planting date obtained only the highest values for sucrose and purity percentages. On the other hand, the 3^rd planting date recorded the highest values of roots, top, biological and sugar yields (tons fed^-1). Therefore, the 3^rd planting date (during October) was the most effective  date against concerned species of root-knot nematodes on naturally infested sugar beet grown in sandy soil using drip irrigation system.