Aims <p>This study aimed to evaluate the validity and reliability of the Turkish version of the Regret Intensity Scale, which assesses the regret experienced by nurses during the care process.</p> Methods <p>This methodological study was conducted with 402 nurses. Data were collected using the Nurse Information Form, Regret Intensity Scale and Elements of Regret Scale. Language and content validity were assessed using the Content Validity Index. Construct validity was examined through exploratory and confirmatory factor analyses. Cronbach’s alpha coefficient, item-total score correlation, and Pearson correlation coefficient were used to assess reliability.</p> Results <p>Exploratory factor analysis (<i>n</i> = 193) showed a KMO value of 0.890 and a Bartlett’s test value of 1466.942 (<i>p</i> &lt; 0.001). Factor loadings of the single-factor structure ranged from 0.737 to 0.865. Confirmatory factor analysis (<i>n</i> = 209) indicated good model fit (χ2/df = 2.338, RMSEA = 0.079, GFI = 0.95). The Cronbach’s alpha coefficient of the scale was 0.932 and all items ranged from 0.927 to 0.934. A statistically significant correlation was found with the Elements of Regret Scale (<i>r</i> = 0.490; <i>p</i> &lt; 0.001).</p> Conclusion <p>The Turkish version of the Regret Intensity Scale is a valid and reliable instrument for measuring the regret experienced by nurses in care processes. It is a practical tool for use in clinical practice and research to assess care-related regret in Turkish-speaking healthcare professionals.</p>