Background: To evaluate the correlation between the different traditional chinese medicine (TCM) deficiency syndromes, cancer related fatigue (CRF), and quality of life (QoL) in breast cancer patients. Patients and methods: Ninety-five breast cancer patients were categorized into different qi (氣 qì), blood (血 xuè), yin (陰 yin), and yang (陽 yáng) TCM deficiency syndrome groups (DSGs). We used the ICD-10 for diagnosing CRF. The QoL was assessed by the WHO-BREF and Short Form Health Survey (SF12) questionnaires. The major outcome was to compare the QoL scores between the different TCM DSGs. The second outcome was the intergroup analysis between the CRF and different TCM DSGs in breast cancer patients. Results: The patients with qi deficiency (氣虛 qì xu) had a higher correlation with CRF (p=0.001) and poorer QoL both in the WHO-BREF and SF12 survey (p<0.001), whereas the patients with yin deficiency (陰虛 yin xu) had poorer QoL in the psychological (p=0.02) and social aspects (p=0.04). The qi deficiency (氣虛 qì xu) syndrome was closely associated with yin deficiency syndrome (陰虛 yin xu). (p=0.03). Conclusion: Our study confirmed the concept of Qi-deficiency (氣虛 qì xu) in TCM was associated with CRF as identified in cancer care in western medicine. The breast cancer patients with qi deficiency (氣虛 qì xu) have poorer QoL. Treatment of CRF and improving QoL by supplying qi (氣 qì) may warrant further investigation.