The resolution and the relaxation time of poly(butyl acrylate) in latex-state 13C-NMR spectroscopy are associated with local motions of the polymer in a dispersoid. Latexes were prepared by emulsion polymerization of butyl acrylate with ammonium persulfate. The latex-state 13C-NMR spectra were measured at 323–353 K with a spectrometer operating at 399.7 and 100.4 MHz for 1H and 13C, respectively. The half width of the latex-state 13C-NMR spectrum depends on the temperature. The half width and the spin-spin relaxation time, T2, are superimposed onto the master curve with a reference temperature, TX.