Software design methodologies were introduced to manage the scale of complex systems built in imperative languages under demanding work conditions. To some degree, declarative notations have been ignored for systems building because they lack similar design methodologies. Methodologies useful to object-orientation, namely, software architectures, design patterns, reusable libraries, and programming frameworks, are proposed as a model to be imitated by the declarative programming community. The resulting “declarative design methodology” would hasten the reapplication of declarative notations to mainstream software design and implementation.