Aim and objective.  To examine the relationships between critical thinking ability and nursing competence in clinical nurses.

Background.  There are few evidance‐based data related to the relationship between critical thinking ability and nursing competence of clinical nurses.

Design.  A cross‐sectional and correlation research design was used.

Methods.  A total of 570 clinical nurses at a medical centre in southern Taiwan were recruited into this study. Two self‐report questionnaires, the Watson‐Glaser Critical Thinking Appraisal (WGCTA) and the Nursing Competence Scale (NCS), were used to collect data.

Results.  The critical thinking ability of clinical nurses was at the middle level. The highest score for the subscales of the WGCTA was ‘interpretation ability’ and the lowest was ‘inference ability’. The nursing competence of clinical nurses was at the middle level and above. The highest score for the subscales was ‘caring ability’ and the lowest was ‘research ability’. Critical thinking ability had a significantly positive correlation with nursing competence. Critical thinking, working years, educational levels and position/title were the significant predictors of nursing competence, accounting for 32·9% of the variance.

Conclusions.  Critical thinking ability had a significantly positive correlation with nursing competence. The critical thinking ability of clinical nurses with a master’s degree was significantly better than those with a bachelor’s degree or a diploma and nurses with over five working years was significantly better than those with under five years.

Relevance to clinical practice.  The findings of this study can further serve as a reference for nursing education to improve nursing curricula and teaching strategies for nurse preparation. It could also be a guideline for nursing administration personnel in on‐the‐job training and orientation programs for nursing staff.