The aim of the current study was to develop an instrument to determine the professional attitude of nursing students. The data were collected through a scale developed by the authors with the statements on attitude, including 8 sub-groups and 28 items. This was a Likert-type scale, ranging from 5 to 1. The sampling of the investigation comprised 1339 final-year undergraduate nursing students in Turkey. Eight factors were defined depending on the reliability and validity study of the professionalism instrument for nursing students. These factors accounted for 65.5% of the total variance. The correlation of the sub-factors in the scale ranged from 0.71 to 0.84. Cronbach alpha value was 0.90 and Cronbach alpha coefficient for sub-factors was between 0.71 and 0.84. Item test correlations calculated for the validity and the homogeneity of the instrument's items were between 0.30 and 0.63. In conclusion, it was found that the instrument was a valid and reliable assessment tool that can be used to measure professional attitudes of nursing students. (C) 2010 Elsevier Ltd. All rights reserved.