Section 94A of the Constitution Act, 1867

Prior to section 94A being enacted, the provinces had sole jurisdiction over old age pensions. In 1927 the federal government and the provinces agreed on a joint-cost funding system for old age pensions. The cost was shared equally by the federal and provincial governments, and the pensions were administered by the provinces under provincial legislation.^{[10]: 296–298} Following World War II, the federal government took a more expansive view of the need for national social programmes and solicited provincial support for a constitutional amendment to give the federal Parliament jurisdiction to provide old age pensions.^[11] Section 94A was enacted in 1951 authorising federal old age pensions, but with the condition that no federal pension law would affect the operation of any provincial pension law.^[8]

The 1951 version of section 94A only authorised the federal Parliament to create old age pensions, but not supplemental benefits. The current version of section 94A was enacted by constitutional amendment in 1964 to include supplemental benefits, but still with the proviso that any federal pension law would not affect provincial pension laws. This amendment allowed Parliament to include benefits for young survivors of pensioners, or disabled contributors.^[10]: 300

Under the authority of section 94A, in 1951, the federal Parliament passed the Old Age Security Act to provide pensions and guaranteed income supplements. In 1965, Parliament passed legislation to create the Canada Pension Plan, which applies in all provinces except Quebec. Instead, Quebec has created a provincial plan, the Quebec Pension Plan, which is very similar to the Canada Pension Plan.^[11]

Provincial jurisdiction over pensions and supplementary benefits is based on section 92(13) of the Constitution Act, 1867. Section 94A confirmed that it does not affect that provincial jurisdiction.

Section 94A is unique in providing that in case of conflict between a federal old age pension law and a provincial pension law, the provincial law prevails. The normal rule in division of powers analysis is the doctrine of paramountcy, which provides that in case of conflict between a federal law and a provincial law, the federal law prevails.^[10]: 300