Rheumatoid arthritis (RA) is a common, chronic systemic inflammatory disease of unclear aetiology leading to synovial hypertrophy and joint inflammation. It typically presents with symmetrical polyarthritis of small joints of the hands or feet, but can also involve larger joints, and have associated extra-articular manifestations. Diagnosis is based on duration of symptoms, joint distribution, level of inflammatory markers and autoantibodies i.e. rheumatoid factor(RhF) and anty-cyclic citrullinated peptide (CCP) antibodies. The presence of synovitis or effusion, either clinical or subclinical, seen on ultrasound or MRI, is essential for diagnosis. RA can sometimes present with a large joint monoarthritis or oligoarthritis. Although this is an atypical presentation, a diagnosis can be made in the presence of suggestive serology and/or histology. In cases presenting with monoarthritis, careful assessment for differential diagnoses is needed, particularly in the elderly population where other conditions such as gout, calcium pyrophosphate deposition disease and osteoarthritis are common. Early referral of patients with suspected synovitis via the rapid access early inflammatory arthritis clinic results in significant improvements in long-term outcomes. Hence it is important to consider early referral for individuals with synovitis, particularly if this is affecting small joints.