Wafiadini wa Nikomedia (walifariki 303) ni kundi kubwa la Wakristo wa Nikomedia, leo Izmit nchini Uturuki) ambao waliuawa wakati wa dhuluma ya kaisari Diokletian kwa sababu walikataa kuabudu miungu. Walikuwa kati ya 1,000 na 20,000, wakiwemo watoto wao. Wanaheshimiwa na Kanisa Katoliki, Waorthodoksi na Waorthodoksi wa Mashariki kama watakatifu wafiadini. Sikukuu yao inaadhimishwa kila mwaka tarehe 23 Juni au 28 Desemba. Watakatifu wa Agano la Kale Orodha ya Watakatifu Wakristo Orodha ya Watakatifu wa Afrika Orodha ya Watakatifu Wafransisko 20,000 Martyrs of Nicomedia Retrieved on 3 Feb 2018 http://www.santiebeati.it/dettaglio/91326 Michael J. Walsh (30 July 2007). A New Dictionary of Saints: East and West. Liturgical Press, 401. ISBN 978-0-8146-3186-7. Retrieved on 23 August 2012.  Martyrologium Romanum The 20,000 Holy Martyrs of Nicomedia. St. Nicholas Russian Orthodox Church. Iliwekwa mnamo 23 August 2012. Encyclopedia of Saints, Second Edition (2014). Publisher: Our Sunday Visitor; 2nd ed. edition (July 2, 2014), ISBN 1612787169 Orthodox Church in America, 28 December