The food industry mostly uses petroleum-based plastics for food packaging which are not biodegradable. The blending of maize starch and zein have been under extensive investigation to produce a thermoplastic starch-zein composite film with improved material properties. A major drawback is that starch and zein are not compatible, as starch is hydrophilic and zein is hydrophobic. Many researchers have reported immiscibility between starch and zein which leads to a composite film with poor material properties. Starch and zein compatibility may be improved under alkaline conditions (NaOH solution) due to the deamidation of zein and starch alkalization. The two biopolymers may better interact with ionic interaction between the negatively charged zein, Na+ and starch alkoxide. The improved interaction between these two biopolymers may produce a composite film with improved material properties. In this research thermoplastic starch-zein composite films were produced under alkaline conditions (0.05M, 0.1M and 0.2M NaOH/Ca(OH)2 by hot melt blending and their compatibility, mechanical, thermal and barrier properties are being investigated. The starch-zein composite film formed by hot melt blending under alkaline conditions are expected to be more homogeneous, with higher tensile strength, lower water vapour permeability and with one glass transition temperature for starch and zein compared to the composite films formed without the alkali (control).