Obstructive sleep apnea syndrome (OSAS) is a condition characterized by recurrent episodes of obstruction of the upper airway. The aim of this study was to evaluate whether nasal obstruction due to allergic rhinitis constitutes a risk factor for OSAS. Patients (n = 119) presenting typical symptoms of sleep apnea were tested for OSAS using polysomnography. Additionally all patients were tested in vivo and in vitro (including nasal eosinophilic cationic protein) for allergic rhinitis. Examination for allergic rhinitis revealed that 88.3% of all patients had no allergic rhinitis, whereas only 11.7% were diagnosed as allergic. No significant differences in sleeping parameters were observed between allergic and non-allergic patients. Comparison of parameters indicative of relevant OSAS (apnea-hypopnea index [AHI] > 10) revealed that 60% of non-allergic patients had relevant OSAS, compared to only 50% of allergic patients. Investigation of allergic subgroups revealed similar results: no significant differences in sleeping parameters or elevated rates of relevant OSAS parameters were observed, especially in perennial allergic rhinitis due to house dust mites. No elevated rates of allergic rhinitis were observed in the studied cohort of patients suffering from sleep apnea or OSAS. Furthermore, no significant differences in sleeping behavior or polysomnography parameters were found on comparing allergic and non-allergic patients. In summary, our data rule out allergic rhinitis as a major risk factor for OSAS.