TheC. elegansvulva is a polarized epithelial tube that has been studied extensively as a model for cell-cell signaling, cell fate specification, and tubulogenesis. Here we used endogenous fusions to show that the spectrin cytoskeleton is polarized in this organ, with conventional beta-spectrin (UNC-70) found only at basolateral membranes and beta heavy spectrin (SMA-1) found only at apical membranes. The sole alpha-spectrin (SPC-1) is present at both locations but requiresSMA-1for its apical localization. Thus, beta spectrins are excellent markers for vulva cell membranes and polarity.