The research and drug development process in rare diseases is challenging in addition to those for common diseases. To stimulate its development, the orphan drug designation (ODD) was introduced in in European Union in 2000. In the present paper, we describe the main characteristics of ODD in European Union in particular the requested criteria for ODD, the overview of the general procedure and the main incentives for Sponsors and finally the predicted factors related to successful development and marketing approval of orphan drugs after designation. In accordance with regulation, an application for ODD must be submitted to European Agency including a scientific part based on relevant scientific literature related to the condition and results on experimental studies with the specific product (and clinical studies if available). Three following criteria are a central position in this application: medical plausibility, rarity and medical significant benefit. The Committee for Orphan Medicinal Products (COMP) is the European Medicines Agency's (EMA) committee responsible for recommending orphan designation of medicines for rare diseases. Even if pre-submission meetings are not mandatory, EMA strongly encourages sponsors to request a pre-submission meeting with the Agency prior to filing an application. Experience has shown that they have a positive impact on the success rate of the applications. The full application should be submitted in English via secure online portal. ODD makes the sponsor eligible for a number of orphan incentives including the 10-year market exclusivity and the protocol assistance by COMP. Based on literature and on the experience accumulated by our team ORPHANDEV F-CRIN-labelled platform the successful translation of rare disease research into orphan drug discovery is dependent of a clearly justified medical significant benefit, the disease class, its prevalence and the disease-specific scientific output, previous experience of the sponsor with a previous successful orphan drug to the market increased.