In 1961, the ONA was originated by Rod Rekofski and other Waterloo Coin Society (WCS) members who decided to hold a meeting (October 7th, 1961 London, Ontario) with club representatives from various numismatic clubs in Ontario to decide on the creation of a Ontario association. This successful meeting determined the formation of the ONA and its founding convention held in conjunction with the WCS's Annual Banquet. Delegates of the first official ONA annual meeting recognized the need for a non-profit organization to serve the education and social needs of Ontario numismatic clubs and hobbyists, and so the ONA was incorporated in 1962.  Members of the first ONA Executive were: President Rod Rekofski, First Vice-President Lloyd T. Smith, Second Vice-President Ed Knight, Secretary Ruth Mueller, Treasurer Bruce Raszmann, and Regional Directors Walter Griggs, Rudy Sauro, Peter DeGraff, and Robert Willey.

The founding 1962 convention held at the Walper Hotel (Kitchener) and hosted by WCS had the support of over 700 in attendance and 250 for the banquet.  ONA Conventions have been held in most major Ontario cities from Windsor to Ottawa and from Sudbury to Niagara Falls. The ONA continues to be an active and prosperous organization which continues to search out new ideas to improve the numismatic hobby for clubs and individual collectors.

The ONA Motto is "VIRES ACQUIRIT EUNDO" translating to "AS IT GROWS, IT GATHERS STRENGTH". The accomplishment of the ONA over the years since its conception, prove the validity of its motto.