Biotechnological drugs have become an essential part of modern pharmacotherapy and are expected to reach a 50% share in the pharmaceutical market in the next few years. The expiry of patent protection for many original biotechnological medicines has led to the development of what are called biosimilars or follow-on biologics. Biosimilars attempt to copy the original technology leading to the production of innovative biotechnological medicines to obtain a product which is similar to the original one. The first two biosimilars have recently been approved in the European Union and one application was rejected. Many more biosimilars will likely see approval in the near future. Our experience with biosimilars has been very limited to date and long-term safety data including immunogenicity are not available. Although biosimilars will likely lower the cost of modern therapies there are issues which have to be discussed at this stage among physicians regarding in particular the differences between biosimilars and generics of the classical chemical drugs, need for appropriate regulations as well as identification of potential problems with biosimilars. Other specific problems which will also be addressed in this review are safety of biosimilars, pharmacovigilance, automatic substitution, naming and labeling/prescription rules.