X-ray powder diffraction data for 1-(4-Nitrophenyl)-2-piperidinone, C11H12N2O3, are reported [a = 9.514(3) angstrom, b = 12.308(6) angstrom, c = 9.175(1) angstrom, alpha = 90 degrees, beta = 91.811(2)degrees, gamma = 90 degrees, V = 1073.94 angstrom(3), Z = 4, rho(cal) = 1.362 g cm(-3) and space group P2(1)/n]. All measured lines were indexed and are consistent with the P2(1)/n space group. No detectable impurities were observed. (C) 2015 International Centre for Diffraction Data.