Paraneoplastic endocrine syndromes define a group of secondary signs and symptoms associated to a neoplasia, independently from the location of the primary tumor or its metastases. Paraneoplastic or ectopic endocrine syndromes usually result from aberrant hormone precursors or hormone-like substances by tumours. Knowledge of paraneoplastic endocrine complications is important both for the early diagnosis of neoplasia and the prognosis of the patient. In this review we discuss almost all reported paraneoplastic endocrine syndromes. We analyze their prevalence, etiology, laboratory diagnosis and treatment.