Adult-onset Still's Disease is a rare auto inflammatory disorder of unknown etiology characterized mainly by high spiking fever, arthritis, evanescent rash and lymphadenopathy. It is a form of systemic onset juvenile rheumatoid arthritis that is encountered in adults, typically between 15-25 years and 36-45years. We here describe a 28 years lady with fever, arthritis of multiple large joints, lymphadenopathy and rash, with negative Rheumatoid factor and evidence of past infection with Ebstein-Barr virus and Parvovirus B19. History, examination findings and investigations showed several features consistent with adult-onset Still's disease along with high ferritin level. After exclusion of probable other diagnosis and use of Yamaguchi criteria, she was diagnosed with adult-onset Still's disease. All the major and minor criteria of Yamaguchi for diagnosis were met. Her disease responded well with steroid, she achieved remission and is currently under maintenance therapy. Keywords: Adult-onset stills disease; arthritis; ferritin; fever.