Extreme programming (XP) has attracted attention because of its fierce denial of many well-accepted software engineering practices considered as a sound approach to the development of intensive software systems. XP has been declared to be a new way of software development: a lightweight methodology, which is efficient, low-risk, flexible, predictable, scientific, and distinguishable from any other methodology. In the core of XP practices are programming activities, with strong emphasis on oral communications, automated tests, pair programming, storytelling culture and collective code-ownership at any time in the XP project. The paper gives an overview of XP practices and raises some serious concerns regarding their role in conceptual modelling and code generation; which directly affects software architecture solutions. The paper also tackles similarities between rational unified process (RUP) and XP, which have often been juxtaposed by software developers.