Background Bipolar disorder (BD) is often misdiagnosed as major depressive disorder (MDD). This study tested the psychometric properties and the accuracy of the Chinese version of the 33-item Hypomania Checklist (HCL-33) to identify BD in Chinese clinical settings. Methods A total of 350 depressed patients were consecutively interviewed in a major psychiatric hospital in China. The patients' socio-demographic and clinical characteristics were recorded using standardized protocol and data collection procedures. The HCL-33 was completed by patients to detect symptoms characteristic of mania and hypomania. DSM-IV diagnoses were established using the Mini International Neuropsychiatric Interview (MINI). Results The HCL-33 showed high internal consistency with two-factorial dimensions. The optimal cut-off point on the HCL-33 to differentiate BD from MDD was 15, while cut-off points of 14 and 13 differentiated BD-I and BD-II from MDD, respectively. The maximum sensitivity was 0.62, 0.67 and 0.72 for differentiating BD, BD-I and BD-II from MDD, respectively. Conclusions The HCL-33 is a useful tool for screening for BD in Chinese depressed patients. The routine clinical use of the HCL-33 as a screening instrument for BD in Chinese patients is recommended.