Widespread application of pesticides in agriculture results in contamination of water sources with such compounds. Diazinon is a major environmental challenge in Iran since it is one of the most commonly used pesticides with adverse effects on human health. Therefore, the current study aimed at fabricating and modifying electrospun nanofibrous membrane (ENM) using iron oxide nanoparticles, and investigating its efficiency in removing diazinon from aqueous environments. The current study investigated the effect of different parameters such as nanoparticle concentration in the membrane (0.01, 0.1, and 1%), and soluble parameters such as diazinon concentration (10, 20, 30, and 40 mg/l), pH (5, 7, and 9), and flux in the removal of diazinon from aqueous solutions. The characteristics of ENM were determined by FTIR, SEM, and XRD analysis, and results showed that, the pure nanofibrous membrane was uniform with mean diameter of 180 nm and porosity of 79%. The results also showed that the highest removal efficiency under optimal conditions (pH 7, diazinon concentration of 10 mg/l, and 0.1% nanoparticles) was 83.7%. The modified ENM with proper mechanical properties and porosity, and high flux can be applied as an effective and environment-friendly material to remove diazinon from aqueous solutions.