Meijer Koekoek was a son of Simon Koekoek and Saartje Hamme, both from Den Haag. 13 March 1918 he married Joanna Maria Theunissen in Rotterdam, a daughter of Petrus Jacobus Theunissen and Maria Teijsen. Meijer Koekoek and his wife had four children, of whom two have died in 1919 at a very young age.
Meijer Koekoek was sent 19/20 August 1942 to Camp Westerbork and deported to Auschwitz 21 August. According notes on his registration card of the Jewish Council, Meijer Koekoek "deceased 23 September 1943, due to weakness of his heart, listing 19-C of the Registry of Auschwitz".
Archive of the Municipality of Berchem (Belgium), bulletin 14731; City Archive of Rotterdam, family registration card of Meijer Koekoek; website www.wiewaswie.nl, marriage Meijer Koekoek and the file cabinet of the Jewish Council, registration card of Meijer Koekoek.