In 1950, the total volume of mail moving through the Canadian postal system was 1 362 310 155 items. By 1966, postal workers were processing 49 billion letters. The increase was enormous, and of course it demanded a larger work force. Between 1957 and 1966 alone, the number of postal staff increased from 30 000 to 44 000. In addition, due to the growth of the cities, letter sorters had to memorize huge amounts of information about letter carrier routes. This reality, combined with the desire to speed up the flow of mail, prompted postal administrators to acquire machines for automating the entire process of sorting, an initiative that inevitably required the introduction of the postal code. This first step in the whole process was taken in 1971.

The submission of a 1969 feasibility report to the Post Office department on establishing a postal code in Canada led to the creation of the Coding and Mechanization Branch the following year. Ottawa was chosen for the pilot coding, and was the first city in Canada to be coded, on 1 April 1971. The work then continued with the coding of an entire province, Manitoba, and finally of the rest of the country.
The Post Office department opted for an alphanumeric code, a flexible system with possible combinations in the neighbourhood of 7.2 million, consisting of six characters (two groups of three) arranged in the following order: one letter/one numeral/one letter followed by one numeral/one letter/one numeral. The three characters in the first group are a regional indicator; the second three are a local indicator. The first letter of the regional indicator refers to a very large area, such as a province or a substantial part of a province. The other two characters indicate an urban area or a group of villages. The characters in the local indicator determine the address of one side of a street, a building in a city or a post office in the country. Consequently, there is real precision in the alphanumeric system. It is superior to the American zip code of only five numerals, which ultimately is equivalent to our regional indicator alone. The British postal code, which is five to seven characters, is closer to our own, but the comparison stops there, for the numerals and letters in that system are not always in the same order. The postal code, which depended on the use of an Optical Character Reader (OCR), at first had to be typed so that it could be machine-readable. Since 1990, however, it has been possible to read handwritten codes thanks to the Multiline Optical Character Reader (MOCR), a machine, which, in 1994, could also cancel letters. With this equipment, 30 000 letters can now be processed in one hour. However, the introduction of the postal code with its attendant upheaval of the work environment did not pass without friction. The job losses caused by automation raised the ire of the unions. The 1970s were punctuated by a series of strikes, compounded by a national campaign to boycott the postal code (1972-1976). The union movement attempted to persuade citizens and business people to refrain from using the postal code until postal workers had received their fair share of the profits generated by use of this new technology. The tense labour climate of the time made these years among the most difficult in post office history. But, the fact remains that the total mechanization of mail processing ushered in by the postal code was one of the biggest changes in the Canadian postal service since its beginnings.

Gérald Pelletier


Gendreau, Bianca. “Présentation à l’ACFAS, 25 mai 1995.”

Lacasse, Germain. “Le tri postal au seuil du 3ème millénaire.” Canadian Postal Museum research paper, January 1999.

O’Reilly, Susan McLeod. On Track: The Railway Mail Service in Canada. Hull: Canadian Museum of Civilization, 1992.

“The Postal Factory,” Canadian Postal Museum research paper.

Vardalas, John. “Moving up the Learning Curve: The Digital Electronic Revolution in Canada, 1945-1970.” Ph.D. Thesis (History), University of Ottawa, 1997. See chapter 5, “Moving the Mail and People.”