On November 21, 1989, Dattilo was appointed the eighth bishop of the Diocese of Harrisburg by Pope John Paul II.
[2] He received his episcopal consecration on January 26, 1990, from Archbishop Anthony Bevilacqua, with Bishops William Keeler and Donald Wuerl serving as co-consecrators, at St. Patrick's Cathedral in Harrisburg.
[2] As bishop, Dattilo began a three-year Consultations Process to assess the needs and resources of the local church in preparation for the next century.
[1] Nicholas Dattilo died at Holy Spirit Hospital in Camp Hill, three days before his 72nd birthday.
[1] His funeral Mass was at Good Shepherd Church in Camp Hill, as St. Patrick's Cathedral was undergoing renovations.