Mamluk architecture in Egypt is varied and widely multiple. Although variety of the motives for erecting mamluk architecture, the vow (naḏr) was not studied as a reason for constructing mamluk buildings. This research aims at studying the impact of vow on the mamluk architecture in Egypt whatever this architecture is religious or secular. It illustrates buildings constructed because of the vow. Additionally, this research points out to architectural units renovated in some Islamic structures as a fulfillment of vow. The study utilized an inductive methodology by examining historical accounts from the primary sources according to analytical approach. It also employed a descriptive approach to illustrate some remained mamluk structures, in addition to architectural units renovated because of the fulfillment of vow. The study concluded that vow is the main reason for constructing five mamluk structures, they are: Market of Ambergris (Sūq al-ʻAnbarīyyn), hospital of Qalāwūn (Bīmārīstān), Khanqah of al-Nāṣir Muhammad b. Qalāwūn at Siryāqūs, Mosque of al-Mūʼyyad Shaykh and mosque of sultan Barsabāy at al-Khanka. Additionally, Sultan Lājīn restored the mosque of Aḥmad b. Ṭūlūn to fulfill his vow as a form of obedience to Allah