As the largest secondary metabolite to be discovered as of yet, the polyether marine neurotoxin maiitotoxin constitutes a major structural and synthetic challenge. After its originally proposed structure (1) had been questioned on the basis of biosynthetic considerations, we provided computational and experimental support for structure 1. In an effort to provide stronger experimental evidence of the molecular architecture of maitotoxin, its GHIJKLMNO ring system 21 was synthesized. The C-13 NMR chemical shifts of synthetic 3 matched closely those corresponding to the same domain of the natural product providing strong evidence for the correctness of the originally proposed structure of maitotoxin (1).