Thai Cultivar Date Palm (KL1) (Phoenix dactylifera cv. KL1) has been grown in Thailand for decades. Mature fruits are popular for fresh consumption. However, 50% or more of the fruit production was thrown away each year because of its low quality. To help farmers avoid wasting huge amounts of money, these low-quality fruits were preliminary developed into three value-added products. The fresh juice and its processed products were analyzed for types and amounts of sugars. The ripened date fruit was boiled and filtered to yield “boiled juice.” The juice was sterilized further using the retort technique under high temperature and pressure and called “retort juice.” The date-boiled juice was also concentrated to yield “syrup.” The type and amount of sugars contained in date palm fruit and its developed products were analyzed by a validated HPLC-RI detector. The injection volume of 3 µL was performed at 30°C with a flow rate of 1.4 mL/min using 75 % acetonitrile with 25% water as a mobile phase. The retention times of the containing sugars were compared with standards. Thai Cultivar Date Palm (KL1) and its products contained higher amounts of monosaccharides than disaccharides. The mean values of fructose, glucose, and sucrose were in the range of 0.1449 – 1.4227 g/100 mL, 0.2539 – 1.6696 g/100mL, and 0.0893 – 0.3019 g/100mL, respectively. Galactose and maltose could not be detected. Among the products, syrup contained the highest amount of total sugar, followed by the retort juice, the boiled juice, and the fresh date juice, in order from highest to lowest in sugar content. The waste date fruit could be developed into other value-added products. These products are a source of fast energy drinks, due to the high amount of monosaccharides that are easier to absorb into gastrointestinal cells than disaccharides. The sugar contents increased significantly by temperature and time of heating. This paper is the first report on sugar analysis of Thai Cultivar Date Palm (KL1).