A 22-year-old female with ulcerative colitis that was successfully treated with infliximab (IFX), and remained stable following tapered discontinuation of prednisolone, developed anterior neck pain and elevation of C-reactive protein following her fourth administration of IFX. She was diagnosed with Takayasu arteritis (TA) based on neck ultrasound and computed tomography angiography. This is the first report describing the development of TA during treatment of UC with IFX.