ABSTRACT: The Citadel of Salah El-Din is located near the center of Cairo on the slope of Gebel Mokattam, built on strata of the Middle Eocene Mokattam Formation, which yields Nummulites praelyelli Boukhary and Kamal 2003, the ancestor of Nummulites lyelli Archiac and Haime 1853. Nummulites sp. cf. N. praelyelli collected from the nummulitic bank at the base of the Citadel tombs section is named after the citadel tomb which is a cemetery below GebelMokattam known since Mamluk times of the 14th century, H.D. The described Nummulites belong to the Nummulites partschi group (s. l.) which the authors propose to subdivide into three subgroups: N. partschi (s. s.), N. gizehensis and N. lyelli. According to the nature of their septa, the species N. praelyelli and Nummulites sp. cf. N. praelyelli should belong to the N. lyelli subgroup of the N. partschi group. The studied Nummulites are described, biometrically studied and photographed. With reference to the scheme of Serra-Kiel et al. (1998), the considered biostratigraphic interval is assigned to SBZ 16.