This paper presents the outcomes of an experimental program conducted on two equal span continuous RC flanged composite girders aiming to enhancing their cracking characteristics at the negative moment zone. Internal prestressing technique associated with high-strength concrete was selectively chosen and implemented in the negative moment zone of the intermediate support. Thus, five continuous RC girders were prepared and tested under repeated loading. The test specimens were divided into two groups; namely, reference and strengthened group. The reference group consisted of one monolithic girder and another composite girder where the flange was casted two week after casting the web. The strengthened group had three composite girders where the negative moment zone of the intermediate support was casted with high-strength concrete. Internal un-bonded steel fasteners were used in order to keep the integrity between the web and the flange at the negative moment zone for the three specimens of the strengthened group. Whereas, prestressing on the main tension steel were applied with two different prestressing level for two specimens only of the second group. It was found that, the adopted hybrid enhancement technique improved the cracking characteristics at the service load stage, however this enhancement effect was decreased approaching the failure.