Objectives. Pittsburgh Sleep Quality Index (PSQI) values correlate with depression, but studies investigating the relationship between PSQI values and polysomnographic (PSG) data showed inconsistent findings.Methods. Sixty-five consecutive patients with multiple sclerosis (MS) were retrospectively classified as “good sleepers” (GS) (PSQI ≤ 5) and “poor sleepers” (PS) (PSQI > 5). The PSG data and the values of the Visual Analog Scale (VAS) of fatigue, Modified Fatigue Impact Scale (MFIS), Fatigue Severity Scale (FSS), Epworth Sleepiness Scale (ESS), and the Beck Depression Inventory (BDI) were compared.Results. No significant differences were found either for PSG data or for ESS, MFIS, and FSS values; but PS showed significantly increased BDI and VAS values.Conclusions. Poor sleep is associated with increased depression and fatigue scale values.