That research studied the percentage of decreasing or increasing in the cost of building by using interior height 2.70 & 3.20 and 3.70m for every floor from three Ville's (A, B and C) in the coastal zones in Hadramout Government in Yemen. That means that the decreasing or increasing in the height of the floor is in a relationship with the cost of materials of the building, working peoples and the time of executing. We have a result that about 12.0% to 17.0% decreasing or increasing in the total cost when we decreasing or in creasing 50 cm from or to the height of the floor from 3.20m to 2.70m. That research aims to have an economical study for the suitable height in the case of saving costs in the housing projects in urban areas in Yemen, generally for the government and specially for particular sector. The research finished with some important results and considered that very important to put rules in the low to be legal for executing and out the suitable interior height 2.70m height of the floor all for the types of buildings as (administration buildings & Healthy B. & Education B. & Services B. & Housing B. .. ect). The main aim is to realize economic in building in the urban areas in Yemen