Sleep and anxiety problems occur in hemodialysis (HD) patients due to physical symptoms, lifestyle changes, and psychosocial changes. To remove these sleep and anxiety problems, lavender oil inhalation is one of the nonpharmacological treatment options with less adverse effects than pharmacological methods. The purpose of this study was to determine the effect of lavender oil application via inhalation pathway on HD patients' anxiety level and sleep quality. The study was conducted with 34 HD patients who have been on HD treatment at 2 dialysis centers. The patients of the intervention group (n = 17) were told to drip 2 drops into the box and to place it 15 to 20 cm away from the pillow, 30 minutes before going to bed for 1 week. Control group (n = 17) received no intervention. Data were collected with questionnaire form, Visual Analog Scale, and Hamilton Anxiety Assessment Scale with a face-to-face interview. Subjective sleep quality of the intervention group was higher than that of control group, mean Visual Analog Scale daytime sleepiness score declined (P < .05), and mean score of sleep duration increased (P < .001) in the intervention group. However, the differences of mean score of time for falling asleep between the 2 groups were not different. The mean score of total and subdimensions of Hamilton Anxiety Assessment Scale of intervention group and control group was significantly different (P < .001). These study results provide new promising information about the effect of lavender inhalation on sleep problems and anxiety and these have made significant contributions to nursing, especially for dialysis nurses.