Restless legs syndrome (RLS) is characterized by unpleasant sensations, pain in the legs along with irresistible urges to move the legs when at rest. It is often accompanied by sleep disturbance. The purpose of this study was to assess the association of anxiety and sleepiness with sexual function in hemodialysis patients with and without RLS. Sociodemographic parameters, laboratory data of hemodialysis patients from three dialysis centers were collected prospectively. Anxiety, sleepiness, sexual function, and presence of RLS symptoms were assessed with standardized questionnaires as the RLS Diagnosis and Scale, Hamilton Anxiety Rating Scale, Epworth Sleepiness Scale (ESS), Arizona Sex Experiences Scale (ASEX). Univariate, regression tree method were used for statistical analysis. RLS was observed in 45.9% (n=113) of hemodialysis patients (n=246). The mean age of patients and duration of hemodialysis were 59.7 +/- 14.0 and 4.9 +/- 4.2 years, respectively. The correlation between Arizona Sexual Experiences Scale (ASEX) and sociodemographic features was significant (P<0.0001). Patients with RLS had higher scores for anxiety (9.4 +/- 7.8 with RLS and 6.8 +/- 6.0 without), higher ESS (ESS, 6.6 +/- 5.2 with RLS and 4.6 +/- 4.0 without), and higher ASEX (24.6 +/- 5.7 with RLS and 22.5 +/- 6.8 without) than did those without RLS. The presence of RLS symptoms in hemodialysis patients was associated with sleepiness, anxiety, and sexual dysfunction. A regression tree method, which is a different statistical method, can help physicians estimate patients ASEX, RLS, ESS, and anxiety scores.