Problem solving in clinical nursing practice is the essence of good care delivery. This paper gives an overview of a research study which identified the cognitive problem solving process nurses use while delivering care. The study was conducted in the clinical setting and used a qualitative research methodology of observation, followed by in-depth semi-structured interview. The analysis of the study revealed diagnostic reasoning is the process used by clinicians. Information regarding the differences between novices and experts is offered as topics for discussion throughout the paper, and recommendations for changes to educational processes are made.