There has been some confusion regarding Sole Source solicitations and Section 508 compliance. The FAR is very clear that Section 508 should be considered in ALL solicitations, with the following exceptions: National Security, ICT acquired incidental to a contract, "back office", and Undue Burden (FAR Subpart 39.2 Information and Communication Technology). Undue Burden can only be claimed after the agency has conducted accessibility market research to determine that it would create a significant hardship on the agency. Commercial non availability, which can also be the basis for a Sole Source justification, is like undue burden in the sense that it can only be claimed after accessibility market research has been completed and approval has been received from the agency. Claims for both Undue Burden and Commercial non availability MUST be documented and included in the contract file, see FAR 39.203(c)(2) and 39.204(e)(2)(i). There is no requirement to include this information in solicitation documents, but we highly recommend doing so as a good business practice. If Sole Source contracts do not include proof of conformance to Section 508 requirements or documented claims for either Undue Burden or Commercial non availability in the contract file, they could result in an administrative complaint by a user or a legal action by a vendor excluded from bidding on the contracts. Section 508 requirements along with other technical requirements define acceptance criteria for the Sole Source deliverable.