Abstract: Objective:To observe the effect of dexmedetomidine on sleep and anxiety in cancer patients who received chemothera-py. Methods:Sixty cancer patients suffering from sleep disorders or anxiety symptoms and receiving chemotherapy between March and June 2014were randomly divided into treatment and control groups. The patients in the treatment group were treated with intrave-nous drip of 1.0 μ g/kg dexmedetomidine for more than 30min, once a day for three days. The patients in the control group were given the same dose and drip time of normal saline. Athens Insomnia Scale (AIS) was used to assess the sleep quality of patients before and the 1st, 2nd, and 3rd days after the administration of dexmedetomidine. Self-Rating Anxiety Scale (SAS) was employed to assess anxi -ety before and the 3rd day after the administration of dexmedetomidine. Results:Compared with the control group and status before ad-ministration of dexmedetomidine, the AIS scores were significantly lower in the 1st, 2nd, and3rd days after administration ( P<0.01), and the SAS scores were also significantly lower in the 3rd day after administration  ( P<0.01). Conclusion:Dexmedetomidine may im -prove sleep quality and alleviate anxiety symptoms in cancer patients undergoing chemotherapy.