Biosimilar medicines are biological medicinal products that can obtain a marketing authorization in the EU after the original product (biological reference medicine) has run out of patent. As a prerequisite, studies including clinical trials are to be conducted to compare the quality, safety, and efficacy of the biosimilar and reference medicine. Due to the specific characteristics of biopharmaceuticals like complex 3-dimensional (glyco) protein structure, immunogenicity, production in living organisms, which causes heterogeneity, complex manufacturing process and analysis, interchangeability of the biosimilar with its reference drug product is not guaranteed. In addition, INN (international non-proprietary name) naming and interchangeability, pharmacovigilance, and traceability are subjects for discussion. The aim of this article is to describe the pharmaceutical and pharmacological specialties of biosimilars and to inform about points to consider (like manufacturer, good handling practice, pharmacovigilance, costs), when the use of biosimilars comes into question.