Demolished concrete structures proven to be a good source of construction materials. This paper studies the utility of using recycled construction rubbles to improve some properties of compacted subbase .Different subbase materials were produced with 0%, 25%, 50%, 75% of recycled construction rubbles aggregate as a partial replacement of natural subbase. The standard tests were conducted on the choosed maerials before and after the replacement. It is found from the test results that the recycled construction rubbles can be used significantly to improve the properties of some types of subbase. The CBR values of the subbase materials prepared with crushed concrete, recycled bricks, and ceramic rubbles as a partial replacement were better than those of natural subbase materials. The performance of subbase containing crushed concrete rubbles was better than the performance of subbase containing crushed clay bricks and ceramics. The CBR values for all subbases were greater than 45%, which is accepted as per the requirements CRB specifications in Iraq.