Sugarcane is an important crop in tropical and sub-tropical regions and this crop has a great economic impact on both social and governmental issues. It is vulnerable to attacks of arthropod pests and, among them, pink stalk borers Sesamia spp. (Lepidoptera: Noctuidae) are one of the most detrimental insect pests of sugarcane in Iran. Damage by this genus of stalk borer can reduce the quality and decrease the sugarcane production, and in severe attacks the tonnage of recoverable sugar will be greatly reduce. Management of this pest is through integrated tactics based mainly on biological and cultural controls. Therefore, assessment of the spatial distribution of Sesamia spp. populations is very important for best management programs on different commercial cultivars. The aim of this study was to determine spatial distribution of Sesamia spp. on two sugarcane cultivars CP69-1062 and CP48-103. For each cultivar, one first-ratoon field (15 ha) was selected and 100 points (with 20-m distance between each point) were randomly chosen. Sampling was started in mid-April 2014 and continued every month until September 2014. Because of sugarcane morphology in April and May (tillering stage), at each point 100 shoots were selected at random and the number of “dead hearts” were recorded. In sampling from June until September (growth stage), at each sampling point, 20 stalks were sampled, and the number of bored stalks was assessed. To determine the distribution of Sesamia spp. on each cultivar and at different sampling times, several classical statistical indices were used. In CP69-1062 and CP48-103 and at each sampling period, Sesamia spp. have aggregated spatial distributions. In all stages and cultivars, the variance/mean ratio (dispersion index) was above 2; Morisita's index was gretaer than 1, Green's coefficient was below 0.5, and the k index (k moment) was below 2 - all indicated aggregation. The results confirm that behavior of Sesamia spp. at different stage of sugarcan