Sarcoidosis is a chronic disease, which predominantly affects the lung. Since sinonasal sarcoidosis is rare, little is known about the sarcoidosis manifestation at this site. Therefore, the aim of our study was to detect the prevalence of sinonasal sarcoidosis, its clinical occurrence, diagnosis, and therapy.The database of all patients having visited the otorhinolaryngology departments of the universities in Göttingen and in Bonn between 2003 and 2016 was searched for the diagnosis of sinonasal sarcoidosis.Thirteen patients with a biopsy-proven sinonasal sarcoidosis were identified. Most patients presented non-specific clinical symptoms, which are also found in acute and chronic sinusitis. None of the patients was suspected to have sinonasal sarcoidosis by the ENT doctor before histological validation. The mean diagnostic delay was 262 (± 195) days. An additional pulmonary involvement was detected in four of six patients.Sinonasal sarcoidosis is presenting with heterogeneous clinical presentations. An early biopsy of granulomatous lesions is mandatory. A multidisciplinary approach is needed to exclude serious lung or heart manifestations, because even asymptomatic organ involvement is possible. A CT-scan may be useful even if unspecific. Local or systemic therapy has to be prepared individually using local and systemic corticosteroids, antimetabolites, or anti-TNF-alpha.