Three aromatic glycosides, lucumin, lucuminamide and lucuminic acid, were isolated from the seeds of Calocarpum sapota MERRILL (Sapotaceae). We studied the seeds of Calocarpum sapota with the aim of isolating the biologically active constituents and report the structure elucidation of these three aromatic glycosides. Their structures were established by spectroscopic methods, chemical evidence, and X-ray crystallography. X-ray analysis determined the absolute stereostructure of lucumin (1) to be 2(R)-[6-O-(β-D-xylopyranosyl)-β-D-glucopyranosyloxy]-2-phenylacetonitrile. Lucuminamide (2) and lucuminic acid (3) were identified as the amide and carboxylic acid derivatives of lucumin, respectively. This is the first report of the isolation of lucumin from Calocarpum sapota and of lucuminamide and lucuminic acid as cyanogenic glycoside related compounds.