Provided are an endoscope system and a method of operating the same capable of assisting in capturing an image defined by guidelines. In order to obtain a reference-equivalent image equivalent to a predetermined reference image for each examination region, an examination image is acquired by imaging an examination region. An at-examination imaging condition acquisition unit acquires an at-examination imaging condition obtained at an acquisition timing of an examination image. A still image saving request signal output unit outputs a still image saving request signal for requesting saving of a still image of the examination image in a case where an at-examination imaging condition satisfies a reference imaging condition for obtaining a predetermined reference image for each examination region.