Object oriented software engineering (OOSE) is becoming a common approach to software development. As third generation OOSE processes are established (eg. OPEN [1] and the Unified Software Development Process [2]) organisations will start to consider OOSE as a mature technology. This recognition will mean that more organisations will go through the process of changing their current software development processes. This paper will report on the experience of one team at a large technical firm as they adopted OOSE processes for a major project. The experience of this team confirms most of what has been previously reported in the literature, and adds two additional observations. The first observation is that other literature in this field does not consider team motivation as a factor that contributes to migration success. The second observation is that other literature does not consider the relative impact of some factors over other factors.