The most common problems in hemodialysis patients are sleep disorders and fatigue. This randomized-controlled experimental study was conducted to determine the effect of aromatherapy applied by inhalation on sleep quality and fatigue level in hemodialysis patients. The study was completed in five hemodialysis centers settled in two provinces with 27 intervention group patients and 35 controls, being totally 62 patients, recruited with simple randomization. Ethical approval, informed consent from the individuals and institutional permission were obtained. Data were collected with a questionnaire form and Visual Analogue Scale (VAS) for fatigue, Piper fatigue scale, Pittsburgh Sleep Quality Index (PSQI), and follow-up forms for the patient and the researcher. Aromatherapy inhalation (sweet orange and lavender oil) was performed before going to bed every day for one month to the intervention group patients. No other application has been made to the control group patients except for standard hemodialysis treatment. All of the forms were performed at baseline and at follow-up at the end of the four weeks (baseline and last follow-up), VAS and Piper fatigue scale were performed during follow-ups at the end of every week (the first, second and third follow-ups). Data were statistically analyzed with Independent Samples t-test, one way analysis of variance, Pearson correlation analysis, chi-square test, Friedman and Mann Whitney U tests and Bonferroni test. p < 0.05 was set as statistically significant in comparisons. Mean total and sub-dimension scores of VAS, Piper fatigue scale and PSQI (except for daytime sleepiness dysfunction sub-dimension) of the intervention and control groups at baseline were not significantly different (p > 0.05). It was found that mean total and sub-dimension scores of VAS, Piper fatigue scale and PSQI of the intervention group significantly decreased in other follow-ups compared to the control group (p < 0.05). Consequently, it was determined that aromatherapy applied by inhalation improved sleep quality, decreased fatigue level and severity in hemodialysis patients. Accordingly, aromatherapy prepared with sweet orange and lavender oil may be recommended to increase sleep quality and to decrease fatigue level of the hemodialysis patients. (C) 2017 Elsevier Inc. All rights reserved.