This data set contains archival raw, partially processed, and ancillary/supporting radio science data acquired during the Extended Mission (EXT) phase of the Mars Global Surveyor (MGS) mission. The radio observations were carried out using the MGS spacecraft and Earth-based receiving stations of the NASA Deep Space Network (DSN). The observations were designed to test the spacecraft radio system, the DSN ground system, and MGS operations procedures; to be used in generating high-resolution gravity field models of Mars; and for estimating density and structure of the Mars atmosphere. Of most interest are likely to be the Orbit Data File and Radio Science Receiver files, in the ODF and RSR directories, respectively, which provided the raw input to gravity and atmospheric investigations. The EXT phase began on 1 February 2001. Data were organized in approximately chronological order and delivered on a set of several hundred CD volumes at the rate of 2-3 CD's per week or DVD volumes at the rate of about 2 per month. Typical volume of a one-day ODF was 300-400 kB. Typical volume of an RSR was 5-10 MB, and there could be 0-30 RSR's per day depending on DSN schedules and observing geometry.