The three-photon resonance four-photon ionization and dissociation spectra of dimethyl ether (DME) are presented in the wavelength range 450-550 nm at 1 nm intervals. The (3+1) REMPI spectra show three prominent bands corresponding to the B ← X, C ← X and C' ← X transitions with origins at 61 457 cm -1 (7.615 eV), 59055 cm -1 (7.322 eV) and 58 010 cm -1 (7.194 eV), respectively. Several ionized species, CH 3 + , CH n O + (n = 1-3) and CH 3 OCH 3 + , are observed in the region of wavelengths studied here. In order to compare the results, a shorter wavelength multiphoton dissociation and ionization of DME at 355 nm is also presented. At this wavelength, DME undergoes neutral dissociation to CH 3 and CH 3 O and each fragment is then ionized by multiphoton absorption. The fragmentation at 355 nm is very intense and only small fragments such as CH 3 + , CHO + , CH 2 + , CH + and C + ions are observed. The measurement of photoelectron energy allows us to establish that the DME ionization potential is at least 9.55 ± 0.15 eV. The experiments were performed using a Nd:YAG-OPO (optical parametric oscillator) tunable laser system coupled to a time-of-flight mass spectrometer and a hemispherical electron energy analyser.