This study aimed at investigating the effect of the presence of Fe(II) cations on the stability of oil-in-water (O/W) emulsions produced by membrane emulsification. Both stirred and cross-flow emulsification methods have been used. The influence of fluid dynamics parameters and phases composition has been investigated. Results have shown that Fe(II) negatively affects the stability of O/W emulsions and that the destabilization effect increases with Fe(II) concentration. However, emulsion stability also depended on emulsification variables, such as percentage of emulsifier, emulsified oil percentage, and membrane pore size. In particular, the main destabilization phenomenon is the decrease on the net charge of the emulsion droplets, which causes agglomeration of the droplets resulting in coalescence and, in some cases, breakage.