The crystal structure of N-[(6-methoxy-4-oxo-1,4-dihydroquinolin-3-yl)methyl]-2,2-dimethylpropanamide (2) was determined by X-ray diffraction analysis. The compound crystallized in the triclinic system, space group P1, with cell parameters of a = 7.829(3)Å, b = 8.995(4)Å, c = 10.646(5)Å, α = 85.86(2)o, β = 86.99(1)o, γ = 88.00(2)o, and Z = 2. The structure was refined by full-matrix least-squares to final values of R1 = 0.049 and wR2 = 0.103. The intermolecular hydrogen bonds of the type N-H···O were observed in the structure. 2004 © The Japan Society for Analytical Chemistry.