This article is devoted to reflections on how to prevent pre-understanding from influencing the research process and jeopardizing the validity of a study. Influences from preunderstanding are exemplified from empirical lifeworld-led caring science research. Finally, there is a discussion of preunderstanding as a natural attitude and therefore also an important part of the lifeworld. It is concluded that validity requires a self-critical approach. It is suggested that a descriptive analysis, where the findings are fairly close to the data, involves a less problematic approach than research, which requires special attention to pre-understanding in connection with different levels of interpretation.