The effect of surfactant concentration and film area on film stability was investigated in thin liquid films of sodium dodecyl sulfate (SDS) solutions. Film stability was evaluated at various concentrations of SDS solutions and various film areas. In this study, a maximum film stability was observed for the SDS concentration of 200 mM. Interestingly, this concentration also corresponds to the maximum micelle lifetime or long relaxation time (tau(2)). The results also show that film stability decreases with increasing film area, and that the larger films appear to be more sensitive to the micelle stability and structuring effect in the film than films with smaller surface areas.