Microcapsules containing fragrant oils as a core material were prepared by in situ polymerization, using melamine-formaldehyde prepolymer as the wall material. The several parameters, such as stirring times, stirring rates, emulsifier types, emulsifier concentrations, and the viscosity of the core materials, affect the characteristics of the microcapsules. These parameters were investigated by the analyses of microcapsule size, particle size distribution, and morphology. The average microcapsule size decreased with an increase in stirring time, stirring rate, emulsifier concentration, and viscosity of the core material. It was also found that poly(vinyl alcohol) as a protective colloid could enhance the stability of the melamine-formaldehyde microcapsules.