PURPOSE: The purpose of this study was to identify the relationship of fatigue and quality of sleep in patients with cancer. METHOD: The data was collected from January to February 2001. Study objects were recruited K university hospital in Busan, Korea. Their fatigue was measured using the Revised Piper Fatigue Scale developed by Piper et. al(1998), and quality of sleep was measured using Quality of Sleep Questionare by Oh et. al(1998). RESULT: 1) The fatigue score was mean 114.80+/-34.88(range: 22-220). The sub dimension that showed behavior/severity score at 33.70+/-13.89, affective score at 24.23+/-3.33, sensory score at 27.74+/-12.51, and cognitive/mood score at 29.11+/-3.71. And sleep quality score was mean 37.32+/-8.18. 2) There was a significant difference in religion(F=4.157, P= .008), present therapy(F=2.536, P= .043), past therapy(F= 6.625, P= .000), major caregiver(F=3.133, P= .028), and change of weight(F=7.965, P= .006), according to general characteristics in the fatigue in patients with cancer. 3) There was a significant difference in present pain(t=-2.103, P= .037) and change of weight(F=5.484, P= .005), according to general characteristics in the sleep quality in patients with cancer. 4) There was a significant negative correlation between fatigue and quality of sleep(r=- .340, P= .000). CONCLUSION: Patients with cancer experience in fatigue. Increase in fatigue are associated with decreases in quality of sleep. Nurses must provide patients with nursing care about the occurrence of fatigue and interventions to deal with sleep disturbance.