|Abstract:||Ngbaka (Ubangi, Democratic Republic of the Congo, [nga]) contains place co-occurrences that are best analyzed as instances of major place harmony, a previously unattested process. In roots, labials cannot co-occur with labial-dorsals, and initial dorsals cannot co-occur with medial labial-dorsals. Using the framework of Agreement by Correspondence, labials (and certain dorsals) correspond, and agree for place. These processes interact with an additional process where homorganic segments agree in voicing. Asymmetries in place interaction is captured through constraint ranking and definitions, thus simplifying the representation of complex segments. These processes are supported by a statistical analysis of newly-digitized dictionary data.