Background & Aims: critical thinking is an index of cognitive ability. The nurses’ cognitive ability, specifically their ability for information processing and decision making, is the key component of nursing practice. The aim of this study was to determine the relationship between critical thinking and clinical decision making in nursing students of Guilan University of Medical Sciences.

  Material & Methods: Fifty senior nursing students from Guilan University of Medical Sciences participated in this descriptive –correlational study by census. Data was collected using California Critical Thinking Questionnaire and clinical decision making cards by Q-Sort and analyzed by Chi- Square and Fischer Exact tests using SPSS- Pc (v.14).

  Results: Findings did not show a significant relationship between critical thinking and clinical decision making. Chi square test showed a significant relationship between critical thinking and educational average score (p==0.001) and between decision making and history of exposing to patients undergoing Billrut 2surgery (p=0.008).

  Conclusion: Conducting the same research with a larger sample using multiple tools is recommended. The findings could be used as a guide to nursing educational planning.