Baricitinib (Olumiant(TM)) is an orally-administered, small-molecule, janus-associated kinase (JAK) inhibitor developed by Eli Lilly and Incyte Corporation for the treatment of rheumatoid arthritis (RA), atopic dermatitis and systemic lupus erythematosus. JAKs transduce intracellular signals from cell surface receptors for various cytokines and growth factors involved in inflammation and immune function, suggesting JAK inhibitors may be of therapeutic benefit in inflammatory conditions. In February 2017, baricitinib was approved in the EU, as monotherapy or in combination with methotrexate, for the treatment of moderate to severe active rheumatoid arthritis in adult patients who have responded inadequately to, or who are intolerant to one or more disease-modifying anti-rheumatic drugs (DMARDs). Regulatory approval to market baricitinib as a treatment for RA has also been sought in the USA and Japan. This article summarizes the milestones in the development of baricitinib leading to this first global approval for the treatment for moderate to severe active RA in adult patients who have responded inadequately to, or are intolerant to one or more DMARDs.