Abstract: Objective: To investigate the clinical value of preserving intercostobrachial nerve(ICBN) in modified radical mastectomy.Methods: Eighty-three breast cancer patients treated with modified radical mastectomy were divided into the observation group(41 cases treated with preserving ICBN) and control group(42 cases treated without preserving ICBN).All patients were followed up for 3 months to 3 years.The operation time,number of dissecting lymph nodes,indicence rate of sensory dysfunction,limb lymphedema rate and local recurrence rate between two groups were compared.Results: The mean operation time and number of dissecting lymph nodes in observation group were(113.56±5.78)min and(12.28±2.19),respectively.The mean operation time and number of dissecting lymph nodes in control group were(110.17±5.41)min and(12.83±2.13),respectively.The differences of the operation time,number of dissecting lymph nodes and limb lymphedema rate between two groups were not statistically significant(P>0.05).The postoperative sensory dysfunction rates in observation group and control group were 21.95% and 66.67%,respectivly,the difference of which between two groups was statistically significant(P<0.05).The local recurrence of tumor in two groups was not found during the following-up.Conclusions: During dissecting axillary lymph nodes in modified radical mastectomy,preserving ICBN can obviously decrease the incidence rate of sensory dysfunction in ipsilateral medial upper arm and chest wall,which is worthy of promoting.