Abstract Iron has several functions in the human body and its deficiency leads to severe health problems. Food fortification is considered as the most acceptable strategy to combat iron deficiency, but the fortification of soluble iron salts induces many technological problems. Succinylated milk proteins can bind sufficient amount of iron. Many varieties of iron protein succinylates are also available in the market as iron supplements, not as food fortificants. Therefore, the present study was intended to prepare succinylated sodium caseinate (succ. NaCas)–iron complex suitable for food fortification purposes by adopting ultrafiltration technology. Level of iron required for the preparation of complex was standardized on the basis of maximum iron binding ability of succ. NaCas. Diafiltration carried out during the manufacturing process not only removed free iron but also reduced excess succinic acid from the complex. The obtained complex also showed better stability under different conditions encountered during processing. Industrial relevance Centrifugation and ultrafiltration (UF) technologies were adopted in the study, the former used to remove the insoluble iron and latter was used to remove free iron. The presence of both insoluble and free iron may be unacceptable for the food processing. The freeze drying technology was also used to facilitate the availability of iron protein succinylate in the powder form for wide range of food application. The proposed method will help industries to adopt the suitable conditions to produce a novel food fortificant commercially.