Tinnitus is a common health complaint in the general population and many personal and psychological factors play a role in the induction and exacerbation of it. Hence, the aim of the present study was to assess, for the first time in the literature, whether individuals biological rhythms differences, i.e. morningness vs. eveningness, have an impact on the severity of tinnitus. We included 93 tinnitus patients who did not have any underlying systemic or metabolic diseases. The morningness-eveningness questionnaire was used to determine chronotypes and the Pittsburgh Sleep Quality Index was used to assess subjective sleep quality. A Visual Analog Scale was used to assess the severity of tinnitus, using a scale from 0 (no tinnitus) to 100 (most severe tinnitus). The evening-type patients reported more severe tinnitus symptoms than morning-types. These findings suggest that individual chronobiological factors affect subjective estimates of tinnitus severity. © 2014 Taylor & Francis.