This paper describes a system for the automatic creation of digital synthesizer circuits that can generate sounds similar to a sampled (target) sound. The circuits will consist of very basic signal functions and generators that are arbitrarily interconnected. The system uses a “genetic algorithm” (GA) to evolve successively better circuits. First it creates populations of such synthesizers, generates the output and a fitness value of each individual circuit. The ones that are best at imitating the target sound will be kept. They are used for “breeding” to form a new generation where, hopefully, at least some individuals perform better than their parents did. The end result will be a circuit that can create a sound that resembles the target sample. Because it’s a synthesizer we can manipulate the different parameters when generating the sound. We can also get a very compact representation of the sound that can be useful when distributing music over a limited bandwidth communications channel (e.g. Internet). As we shall see, it also gives the user a very powerful tool for creating totally new sounds.