In application of pesticide formulations, use of microemulsion systems offer several advantages over conventional systems such as wettable powders, emulsifiable concentrates (EC's), oil in water emulsions (O/W emulsions), water in oil emulsions (W/O emulsions) and aqueous suspension concentrates. Microemulsion systems are preferred for their long-term thermodynamic stability, low viscosity and ultimate economy. Microemulsion system also enables the usage of the least expensive solvent such as water. Formulation of agrochemical microemulsion is not a straightforward process. However, the pseudo ternary plot is a convenient mean of determining the compositions of microemulsion, macroemulsion and solubilized systems. Identification of specific regions in a pseudo ternary plot makes it possible to arrive at economical composition for microemulsion and solubilized systems. Such compositions gave maximum stability with the optimum usage of surfactants. These microemulsion and solubilized systems when diluted with the inexpensive solvent such as water gave macroemulsion and microemulsion respectively, which were stable over an extended period of time. This paper provides the basis for a simple procedure for the preparation of microemulsion systems employing water, oil, surfactant and cosurfactant.