Purpose: This study examined the effects of heat therapy combined with aromatherapy on pain, flexibility, sleep, and depression in elderly women with osteoarthritis. Methods: This study was designed as a nonequivalent control group quasi-experimental study based upon data acquired through a pre-post test. The experimental group (n=21) was treated using an aroma-permeated hot compress applied to the knee. The cotton towel was heated in a microwave to $45^{circ}C$, and 2~3 drops of lavender were applied on it. The towel was wrapped with plastic bag to prevent aroma leakage and retain heat. The treatment was applied the towel for 20 minutes, three times a day for 3 weeks. The control group (n=24) was not given any treatment. Data were collected using a VAS(100mm) for pain, questionnaire for sleep and depression, and a goniometer for knee flexibility. The data were analyzed with ${chi}^2$-test and t-test using SPSS/Win18.0. Results: There were significant differences in knee pain (p=.001) and flexibility (p<.001), subjective quality of sleep (p=.020) and depression (p=.003) between the groups. Conclusion: Heat therapy combined with aromatherapy may be an effective nursing intervention and self-care technique to ameliorate pain and depression and to improve flexibility and sleep in elderly suffering from osteoarthritis.