The term paraneoplastic syndrome refers to the conditions when tumor-related symptoms are not caused by the size, invasion or metastasis of a tumor, but due to soluble mediators produced or an immune reaction induced by a tumor. Paraneoplastic syndromes occur in about 8% of all malignant tumors. Hormone-related paraneoplastic syndromes are termed paraneoplastic endocrine syndromes. In this short synopsis, the main clinical and laboratory characteristics of the most important paraneoplastic endocrine syndromes are presented including humoral hypercalcemia, the syndrome of inappropriate ADH secretion, ectopic ACTH syndrome. Two very rare diseases, paraneoplastic hypoglycemia and tumor-induced osteomalatia are also briefly presented.