The iSaturday one section edition will be priced 30 p and debut on 7 May.
The i published its first audited circulation data in January and in February posted a figure of 175,714.
The circulation dipped in March by 2.45% but this is attributed to the advertising campaign featuring Dom Joly and Jemima Khan coming off air.
The publisher says that the decision to launch a Saturday edition is to meet consumer demand.
Andrew Mullins, managing director of i and The Independent, says: “The forthcoming Saturday launch reflects the success we have had so far with i. As the circulation figures for i continue to hold strong, it shows the appetite readers in the UK have for a digested quality read.”
The arrival of the i has apparently had little impact on the circulation of sister title The Independent, whose circulation for March only dipped 0.32%.
The Independent was bought by Alexander Lebedev, owner of The Evening Standard, in March last year.
Read an interview with MD Andrew Mullins here.