This case study aimed at disclosing the changing trends of amount of document delivery services (DDSs) in the Medical Library Information System (MEDLIS) of the Korean Medical Library Association (KMLA). The data from 2001 to 2014 in the MEDLIS were searched and analyzed according to year. To know outside environment of DDS, The trend in use of DDS of the Research Information Sharing Service and the journals listed in the Directory of Open Access Journal were presented. The DDS request in MEDLIS decreased year by year from 214,304 in 2001 to 50,352 in 2014 (23.4%). There was an increased number of requests a monthly average from 4,799 in 2009 to 8,157 in 2014 (170.0%) through Research Information Sharing Service. As of 2015, 10,702 journals were listed in the Directory of Open Access Journal. I can find that the continuous decreased request of DDS in MEDLIS which might be originated from the increased number of DDS service through RISS and the increased number of open access journals.