This paper examines the architectural generations of layering of buildings through the categorization of buildings of pre- colonial epoch layering of buildings- 1506 -1884 and colonial epoch layering of buildings- 1884-1961 in Central Business District (CBD) of Mbeya city in Tanzania. The colonial epoch layering of buildings has been divided into two parts, namely, The German Epoch Layering of Buildings (1884 -1917) and The British Epoch Layering of Buildings (1917 – 1961).Layering theories and concepts were reviewed to address the issue of architectural generations specifically for layering of buildings. The Architectural generations of layering of buildings in Tanzania owes its character to a number of borrowed land use planning, zoning and housing concepts especially from Europe. However, rural buildings have remained predominantly a metamorphosed African traditional architecture that is gradually giving way to globalized city forms. Generally, architectural city layering development has been shaped by a number of layering that were carried out in the course of city development.