The temperature dependence of Cs-133 NMR and the relaxation time in a CsMnCl3 single crystal have been investigated with a pulse NMR spectrometer. The Cs-133 resonances of two different groups were obtained. The quadrupole coupling constant of Cs(I) and Cs(II) in CsMnCl3 decreases as the temperature increases. Therefore, the temperature dependence of e(2)qQ/h is explained with a single torsional frequency of the Cs-Cl couple by means of the simple Bayer theory. Also, the relaxation rates (T-l(-1)) for Cs(I) and Cs(II) were observed to increase linearly with increasing temperature. The temperature dependence of the relaxation time, T-l(-1), could be fitted by the approximation of (T-l(-1))(Cs(I)) = [(8.76 x 10(-2))T + 19.37] (s(-1)) and (T-l(-1))(Cs(II)) = [(6.51 x 10(-2))T + 13.71] (s(-1)) for Cs(I) and Cs(II), respectively. Therefore, the linear temperature dependence of the relaxation time may well be accounted for by the direct process of scattering with a single phonon.