OICCU was modelled after the Cambridge Inter-Collegiate Christian Union (CICCU), founded two years earlier, but later incorporated a Daily Prayer Meeting established in Brasenose College in 1867.
The initial members included Francis Chavasse, subsequently Bishop of Liverpool and founder of St Peter's College.
OICCU was a founder member of the Student Christian Movement and followed its lead in liberalizing its doctrine.
The SCM gave them permission to use the old (1879) name and so OICCU was born anew, adopting the Doctrinal Basis of the new Inter-Varsity Fellowship of Evangelical Unions (now UCCF) in 1928.
The International Fellowship of Evangelical Students, the worldwide body to which OICCU belongs, was planned at a conference in Oxford in the late 1930s.
Afterwards, a Standing Committee of prominent past members was established to ensure the Union's long-term continuity in such circumstances and in 1948 they became trustees of the Northgate Hall.
In the following decade Packer, along with Martyn Lloyd-Jones, led a revival of Puritan studies amongst British pastors.
In a slightly later generation, Tom Wright was the OICCU President (1970–71) and published his first book together with other members of his year's Executive Committee.
The lease on the Northgate Hall was given up in the 1980s, and the Union has returned to the peripatetic existence of its earliest years, meeting in various church and public buildings around the city.