The infrared spectrum of (CH3I)-C-13 in the region of the nu-5 band, 1300-1600 cm-1, is measured at a resolution of 0.0025 cm-1 with a Fourier transform spectrometer. In the diad nu-5/nu-3 + nu-6 about 130 perturbation-allowed transitions have been observed. They give two equations between A0 and D0K, and from them A0 = 5.174258(4) cm-1 and D0K = 87.56(7) x 10(-6) cm-1 have been derived by fixing H0K = 0.