OBJECTIVES: The present study was conducted to develop a valid and reliable Blood stasis questionnaire (BSQ), to define its optimum cut-off score, and to examine whether the BSQ score affected cardiovascular autonomic function. METHODS: Three hundred and thirty-eight outpatients (group A) and 61 inpatients (group B) were asked to complete the BSQ. In addition to the BSQ, heart rate variability parameters were recorded for group A. We estimated the internal consistency and construct validity for the BSQ data from group A. Three clinicians determined whether 61 inpatients (group B) exhibited blood stasis (BS), and we defined the optimum cut-off point for the BSQ using the clinicians\' diagnoses and BSQ scores for group B. Finally, the differences in the HRV parameters between the BS and non-BS groups (group A) were examined. RESULTS: The 12-item BSQ exhibited a satisfactory internal consistency (alpha=0.813). In the test of construct validity, a total of three factors (pain-lump, dark blue signs, and trauma) were extracted (total percentage of variance=54.8%). ROC curve analyses showed that the BSQ had a high discriminative ability for BS (AUC=0.948, 95% confidence interval 0.895-1.001). The optimum cut-off score for the BSQ was defined as three points. SDNN, TP, LF, and HF were lower in the BS group than in the non-BS group, indicating that the BS pattern partially caused a decrease in sympathetic and parasympathetic activities. CONCLUSIONS: Our results suggest that the BSQ is a valid and reliable instrument for evaluating BS and BS may partially cause a decrease in cardiovascular autonomic function.