The aim of the study was to validate a new research instrument to evaluate the quality of the clinical learning environment and the supervision given to nursing students by qualified staff nurses. This paper describes the validation process of the research instrument. Dunn's and Burnett's (1995) CLE scale was chosen for the concurrent research instrument to test validity. The theoretical framework of this study draws on empirical research into clinical learning environments and supervision undertaken during the 1980's and 1990's. The sample consisted of nursing students who had undertaken a clinical placement in a hospital setting. The data (n=416) were collected from four Nursing Colleges in Finland. Students evaluated their clinical placements as being 'good' in both instruments. The supervisory relationship was the most important factor in students' supervisory system but this requires a positive atmosphere and a 'good' leadership in order to be effective. The congruence between the instruments in use was high so that it is impossible to note the possible impact of cultural differences in this instrument validation process.