The Interlibrary Delivery Service (IDS) of Pennsylvania's purpose is to provide a cost effective efficient delivery service linking all types of libraries to support timely resource sharing throughout the Commonwealth of Pennsylvania. As an incorporated not-for-profit membership organization, IDS is supported by a state/local partnership which includes a state subsidy and local dues. Through IDS, member libraries share print and non-print library resources to meet the information needs of end users. Currently,  IDS membership includes 409 libraries which comprise the service area of the Interlibrary Delivery Service of Pennsylvania. This total includes 181 Full Member libraries and 228 sites which are Affiliates of Full Member ("Parent") libraries.

It is the mission of IDS to:

• Encourage responsible resource sharing rather than to inhibit shipping through the dues structure.
• Encourage electronic transmission of information where feasible and more cost effective than the physical delivery of an item.
• Encourage broad membership among all types and sizes of Pennsylvania libraries.
• Encourage libraries to endorse the Pennsylvania Interlibrary Loan Guidelines adopted in 2011.
• Engage in responsible ILL practices, including copyright compliance.