Polyurea microcapsules were obtained via interfacial polymerization at the interface of methanolin-cyclohexane, formamide-in-cyclohexane, and N,N-dimethylformamide-in-cyclohexane emulsions. Coumarin-1 was used as a model encapsulant; both dye leaching and encapsulation efficiency were examined. For the methanolin-cyclohexane system, design of experiments was used to assess the influence of five different variables on capsule size. A model was obtained that accurately predicts the size of capsules resulting from a given formulation.