Background <p>To date, there are no clear recommendations for the treatment of a clinically inconspicuous neck (cN0) in sinonasal squamous cell carcinoma. Elective neck dissection or neck irradiation appears too aggressive given the relatively low occult metastasis rates. However, the development of neck lymph node metastases is significantly associated with worse survival, therefore patients at relevant risk need to be identified. The aim of this trial was to evaluate feasibility and safety of sentinel node biopsy for sinonasal squamous cell carcinoma.</p> Patients and Methods <p>This was a prospective, single-arm, open label, multicentric pilot trial (phase II) designed to evaluate the safety and feasibility of sentinel node biopsy (SNB) of patients with sinonasal squamous cell&#xa0;carcinoma and clinical N0 status. 24 h before surgery, radiocolloids were injected around the tumor and lymphoscintigraphy with single-photon emission computed tomography (SPECT)/computed tomography (CT) was performed. After resection of the primary tumor, the sentinel lymph node was identified using a gamma probe and resected via minimal invasive incision.</p> Results <p>At least one sentinel node could be detected in each of the 22 patients, predominantly in level Ib and IIa. The average lymph node yield after SNB was two, and 122.7% relative to the marked lymph nodes. SNB identified two cases (T2 and T4a) with micrometastases resulting in an occult metastasis rate of 9.1%. The procedure was safe and aesthetically satisfactory.</p> Conclusions <p>Sentinel node biopsy for sinonasal squamous cell carcinoma is a feasible and safe procedure to detect occult metastases and identify patients at risk for nodal relapse. The results of the study encourage confirmatory, randomized trials.</p>