Numb chin syndrome (NCS) describes a sensory neuropathy characterized by numbness in the distribution of the terminal branch of the mandibular division of the trigeminal nerve. Benign as well as malignant diseases are known to cause NCS. This is often misdiagnosed, and in some cases the symptom may lead to a late detection of malignancy. Reports of 10 cases in which NCS was the presenting and isolated symptom, caused by extracranial malignancies, drugs, or dental/surgical interventions, are presented. This article outlines the symptoms and the diagnostic approaches taken, provides a short review of the etiology and pathogenesis, and proposes diagnostic criteria and treatment of NCS. Both medical practitioners and dentists need to be aware of the relationship between malignancies and paresthesia of the chin or complete loss of sensation in partial segments of the jaw. In addition, dentists should be aware of the diagnostic limitations of an orthopantomogram to detect underlying diseases beyond localized dental disorders.