Abstract Transitional space was considered as one of important parts in any different building types. These spaces contributed to the connection between many parts of spaces like (inside-inside or inside-outside), even in relationships between parts to parts or the whole building to the parts –and also to the urban context. Previous knowledge that focused on this space among limited types of functional patterns led to surfaced the research problem identified as” the need to identify the Transitional Spaces patterns in domestic houses in Iraq among different period times “. the research hypothese is “The patterns of transitional spaces in domestic Iraqi houses varied according to the function and location and the number of these spaces and these changed over time by drop in their types, in addition to reduce in its functional diversity”. The research methodology was consisting of three stages, first: building theoretical framework about characteristics of these kind of spaces in houses, second: select samples of Iraqi domestic houses from different periods times, third: analyzed finding and drawing conclusions. The research conclude that Transitional spaces are affected by many local environments forces, and by social, economic and cultural activities.