Polarized micro-Raman spectroscopy was carried out on the (001) face of a 0.67PbMg1/3Nb2/3O3-33%PbTiO3 (PMN-33%PT) single crystal. The Raman images revealed the spatial variations of the intensity of the Raman bands, suggesting that the structure in the PMN-33%PT single crystal varied from one micro-area to another. When changing the polarization direction of the incident light with respect to the selected crystalline axes, the intensities of the Raman modes varied periodically. According to the Raman selection rules (RSRs), the angular dependences of the Raman modes indicated that the PMN-33%PT single crystal is in the monoclinic phase. Furthermore, the color patterns in the Raman images were associated with the coexistence of the MA- and MC-type monoclinic phases in the PMN-33%PT single crystal. Our results provide useful information for understanding the microheterogeneity of the relaxor PMN-xPT single crystals with compositions near the morphotropic phase boundary region. Copyright © 2010 John Wiley & Sons, Ltd.