A unique opportunity to document and understand the processes of tidal inlet evolution and morphodynamic interactions presented itself with the breach of Nauset Spit across from the town of Chatham, Massachusetts. In the first twenty-eight months since its formation, the morphological evolution of the new inlet can be characterized into four categories: 1) Inlet mouth widening, caused by the concurrent retreats of the north and south spits that flank the inlet mouth; 2) Cyclical spit elongation, breaching, and terminal detachment; 3) The southward migration of the thalweg of the main channel and its associated shoals; and 4) Shoal growth. ; An edited version of this paper was published by AGU.This publication may be cited as: Liu, J. T., Stauble, D. K., Giese, G. S., & Aubrey, D. G. (1993). Morphodynamic evolution of a newly formed tidal inlet. In D. J. Aubrey & G. S. Giese (Eds.), Formation and Evolution of Multiple Tidal Inlets, Coastal Estuarine Studies, 44, (pp. 62-94), doi:10.1029/CE044 ; Florida Atlantic University. Harbor Branch Oceanographic Institute contribution #826.