The construction of shore protection is expensive, but the alternative of permitting erosion is also expensive. Yet any design of shore protection is based mostly on intuitive concepts. This paper presents an overview of what is lacking in our knowledge, a possible methodology for improving shore protection design and discussions about some of the most important (and often ignored) physical parameters to be considered if shore protection is to perform its task without interfering with the littoral environment.Key words: erosion, groins, seawalls, sediment transport, shore protection.