This research has the main objective of presenting a study on the areas of Human-Computer Interaction (HCI) and Software Engineering (SE), focusing on the importance of integrating HCI in SE, more precisely in the Software Development Process (SDP). More specifically, it concerns the adaptation of the Rational Unified Process (RUP) towards having HCI aspects integrated into its main workflows, generating the Rational Unified Process for Interactive Systems, called RUPi. The RUP is a well-established SDP that intends to guarantee quality by controlling the project schedule, budget, communication, productivity, and trustworthiness. Meanwhile, the RUPi intends to guarantee usability, accessibility, and acceptability by focusing on the users and on their context of use, modeling users' tasks, considering guidelines during the SDP, and defining mechanisms to design the User Interfaces (UIs) and to test their usability.