The West African Currency Board was responsible for issuing currency notes in Nigeria from 1912 to 1959. Prior to the establishment of the West African Currency Board, Nigeria had used various forms of money including cowries and manilas.

On 1st July, 1959 the Central Bank of Nigeria issued the Nigerian currency notes and coins and the West African Currency Board notes and coins were withdrawn. It was not until 1st July, 1962 that legal tender status was changed to reflect the country’s new status. The notes were again changed in 1968 as a war strategy following the misuse of the country’s currency notes.

On 31st March, 1971, the then Head of State announced that Nigeria would change to decimal currency as from 1st January, 1973.The major currency unit would be called Naira which would be equivalent to ten shillings: the minor unit would be called kobo; 100 of which would make one Naira. The decision to change to decimal currency followed the recommendations of the Decimal Currency Committee set up in 1962 which submitted its report in 1964.

The change that took place in January, 1973 was a major one and this involved both currency notes and coins. The major unit of currency which used to be £1 ceased to exist and the one Naira which was equivalent to 10/- become the major unit:

On 11th February, 1977 a new banknote denomination of the value of 20 Naira was issued. This was special in two respects:
The N20(Twenty Naira) banknote was the highest denomination to be introduced then, and its issue became necessary as a result of the growth of incomes in the country; the preference for cash transactions and the need for convenience.
The N20 (Twenty Naira) banknote became the first currency note in Nigeria bearing the Portrait of a Nigerian citizen, in this case, the late Head of State, General Murtala Ramat Muhammed (1938-1976) who was the torch bearer of the Nigerian Revolution July, 1975.
He was declared a national hero on the 1st of October,1978. The note was issued on the 1st Anniversary of his assassination as a fitting tribute to a most illustrious son of Nigeria. On 2nd July, 1979, new currency notes of three denominations, namely, ( N1), (N5), and (N10) were introduced. These notes were of the same size i.e., 151 x 78 mm as the N20 note issued on the 11th February, 1977. In order to facilitate identification, distinctive colors which were similar to those of the current banknotes of the various denominations were used. The notes bore the portraits of three eminent Nigerians who were declared national heroes on the 1st of October, 1978. The engravings at the back of the notes reflected the cultural aspects of the country. In 1991, both the 50k and N1 Notes were coined. In response to expansion in economic activities and to facilitate an efficient payments system, the N100, N200, N500, N1000 were introduced in December 1999, November 2000, April 2001 and October, 2005 respectively.
On February 28th 2007, as part of the economic reforms, N50, N20, N10, and N5 banknotes as well as N1 and 50K coins were reissued with new designs, while a new N2 coin was introduced.

Interesting.