The crystal structure of KR-21042, N-(3-Phenylpropyl )-4-hydroxy-3-methoxyphenylacetamide, was determined by single crystal X-ray diffraction analysis. The compound was recrystallized from a mixture of ethylacetate and n-hexane in monoclinic, space group $P2_1/c$, with a = 16.622(1), b = 6.215(1), c = 15.802(1) ${AA},{;}{eta}=104.97(1)$, and Z = 4 The calculated density is $1.261{;}g/cm^3$The structure was solved by the direct method and refined by full matrix least-squares procedure to the fecal R value of 0.068 for 2332 observed reflections.