This paper discusses concept of public toilet and its history 
development and interior architecture role in achieving its goals 
to enhance the quality of space , Then Interior design 
specifications required in public toilets to achieve required 
sustainability like , natural lighting and ventilation , control 
bacterial infection through self-cleaning materials developed by 
nanotechnology , Then we move to public toilets of fixed 
construction in smart cities with defining it`s concept and the 
role of interior architecture in achieving them , so Studying the 
interaction between the building and the surrounding 
environment was a must by studying fixed toilets in many 
advanced cities . Studying the design of electronic toilets, 
sustainable toilets and the revival of historical and archaeological 
areas was a part of studying various trends in designing public 
toilets in smart cities.