The diocese was founded on 12 May 1559, on territory (central and North Holland) canonically split off from the Diocese of Utrecht, which was simultaneously promoted to archbishopric and became its Metropolitan. In 1592 (during the Eighty Years War, during which the Spanish crown lost Holland) it was suppressed, and its territory was immediately included in the new Dutch Missionsui iuris 'Batavia', soon promoted an Apostolic vicariate.
In 1833, the diocese was restored as (pre-diocesan) Apostolic Administration of Haarlem, which was on 4 March 1853 promoted as Diocese of Haarlem (in 1827 the Concordat established the foundation of a Diocese of Amsterdam but no bishop was nominated).
In 2013, the diocese pastorally served 462,000 Catholics (15.8% of 2,915,000 total) on 2,912 km² in 145 parishes, with 194 priests (161 diocesan, 33 religious), 54 deacons, 557 lay religious (81 brothers, 476 sisters).[1]