The seeds of Mahuad (Lepisanthes rubiginosa (Roxb.) Leenh (LRL) were analyzed for proximate composition and the contents of phenolic acids, flavonoids, and sugars/oligosaccharides. The LRL seeds contained approximately 29% moisture, 10% protein, 2% fat, 16% fiber, 2% ash, and 42% carbohydrate. The major phenolic acids were vanillic acid and p-hydroxybenzoic acid, accounting for 30% and 26% of total phenolic content, respectively. The predominant flavonoids were quercetin (62% of total flavonoid content) followed by myricetin (22%). Proline, methionine, and arginine were the dominant amino acids, constituting 35%, 19%, and 13% of total amino acid content, respectively. Prebiotic fructooligosaccharide (5.3 mg/g) and stachyose (4.2 mg/g) were also found in the LRL seeds. The major fatty acids were palmitic acid (C 16:0, 41%), oleic acid (C 18:1n9, 27%), and linoleic acid (C 18:2n6, 19%). This information reveals useful information about LRL seeds as a potential source of bioactive compounds for future use in various aspects including food, feeds, pharmaceuticals, and cosmetics.