Abstract: Background and Objective: Unsuitable sugarcane which immature or over-mature is imported to the mill, a critical problem, generally occurs in sugarcane production under tropical zone. Therefore, the objective of this study was to determine the sugar accumulation patterns of diverse sugarcane cultivars grown under natural rain-fed conditions in a tropical area. Materials and Methods: Randomized complete block design (RCBD) with 4 replications was used. Seventeen different elite lines, which represent all sugarcane production areas in Thailand, were used as treatments. Brix, commercial cane sugar (CCS) and fibre were collected during 8-15 months after planting (MAP). Results: The sugarcane lines used in these experiments can be classified into 6 groups, namely those that exhibit rapid sugar accumulation and CCS decreases with increasing temperature, rapid sugar accumulation and insensitive with temperature, medium sugar accumulation and decrease with temperature increasing, medium accumulation and insensitive, slow accumulation and decrease with increasing temperature and slow accumulation and insensitive. Conclusion: Seventeen sugarcane cultivars exhibited different sugar accumulation patterns, based on the speed of sugar accumulation and high temperature sensitivity at over-maturity.