He married Ermengarde, daughter of Charles, Duke of Lower Lorraine, and had the following sons:
- Robert II, Count of Namur died without issue and was succeeded by his younger brother Albert
- Albert II, Count of Namur was father of Hedwige of Namur, who married Gerard, Duke of Lorraine. They were the great-great-grandparents of Beatrice, who married Emperor Frederick Barbarossa.
There are some doubts about the correct list of his daughters, as there are two very different lists given in two primary documents.
The "Genealogia ex Stirpe Sancti Arnulfi" lists:
- Count Albert
- Emma of Looz
The "Vita Arnulfi Episcopi Suessioniensis" lists (as siblings of one of the Counts named Albert of Namur, whose parents are not named):
- Count Albert
- Liutgard mother of Emmon Count of Looz, and his brother Otto.
A 3rd relevant source is the Gesta of Sint-Truiden Abbey which also named Countess Ermengarde having a daughter named Lutgarde who married a Count Otto of Loon and was mother to Bishop Balderic II of Liège, brother of Count Giselbert of Loon. As Jean Baerten and other authors have pointed out, this is chronologically impossible, though it is possible Lutgarde could be mother of Emmo and Otto.
Liutgarde and Emma, both with a connection to Looz, are sometimes therefore thought to represent a garbled account of the same person.
- Medieval Lands Project on Albert I, Count of Namur
- Ancestral Roots of Certain American Colonists Who Came to America Before 1700 by Frederick Lewis Weis: Seventh Edition, Lines 149-20, 164-24
- Rousseau, Félix (1936) Actes des comtes de Namur de la première race (946-1196). link Archived 2017-08-11 at the Wayback Machine See for example page XLVIII
- "Archived copy". Archived from the original on 2018-01-13. Retrieved 2017-08-11.CS1 maint: archived copy as title (link)
- "Vita Arnulfi Episcopi Suessioniensis" I.3, MGH SS XV.2, p.879.
- Baerten, Het Graafschap Loon