By using optical second harmonic generation (SHG) technique, we visualized lipid Langmuir monolayers comprised of molecules with an SH active moiety, 1,2-dipalmitoyl-sn-glycero-phosphoethanolamine-N-(7-nitro-2-1,3-benzoxadiazol-4-yl) (NBD-PE), on focussing the shape and polarization structure of the domains. The domain shape visualized by the SHG was the same as that by the Brewster angle microscopy (BAM), while polar structure was identified at the cusps of dendritic domains. These results were foundwell supported by our theoretical prediction in our previous study. (C) 2013 Elsevier B.V. All rights reserved.