In the structure of diseases of the ENT organs, the pathology of the maxillary sinus is the most common, including in children. Some diseases of this anatomical zone are quite rare, especially in children. This pathology includes chronic atelectasis of the maxillary sinus—the silent sinus syndrome (SSS). The disease itself has been known for about 60 years, but only in the last couple of decades the eyes of the world otorhinolaryngology have turned more closely toward the SSS. This is primarily due to both the wider introduction of modern diagnostic radiology and the widespread introduction of endoscopic methods for treating the pathology of the paranasal sinuses and the orbit as well as the improvement of surgeons in this direction. In turn, in children, this pathology began to be studied more carefully even later due to the more complex use of modern radiation diagnostic methods in children and the less common possibilities of surgical endoscopic treatment in pediatric otorhinolaryngology. In children, this pathology is no less relevant than in adults, and in case of incorrect management tactics and late diagnosis it leads to no less sad consequences than in adult patients.