The adult acquired flatfoot is a challenging clinical entity with numerous procedures available to the surgeon for correction of the deformity. In a supple stage II flatfoot, naviculocuneiform arthrodesis with appropriate ancillary soft tissue augmentation and other adjunctive osseous procedures has proven effective with reproducible success. It may be used to balance a symptomatic flatfoot, re-establishing medial column stability and alignment while maintaining essential tri-tarsal joint motion. In addition to a review of the evidence-based medicine regarding this procedure, a detailed surgical technique is provided.