To understand the processes of institutional evolution, the author has examined a few notable changes that have occurred with regard to an important informal institution called Kadakkodi, that prevails among the coastal fishing community of Kerala, India. Though it literally means ‘Sea Court’, it functions as a legislative executive and judiciary body that enacts regulations for fishing operations, enforces the regulations and resolves conflicts. Within a short period between early nineteen seventies and mid eighties it was observed that in some villages this system disintegrated while in some other villages it got restructured and restrengthened and in a few villages, the system persited without any interruption, Also it was found in the south Kerala coast, such a system did not emerge at all. The analysis of these four institutional changes finds that among the factors that influence the evolutionary trajectory of kadakkodies, the most important are relative resource endowment, technology, cultural endowment and the already existing institutional structures in the concerned societies of resource users. Variations in the levels of heterogeneity of these factors do explain a major part of the variations in the evolutionary processes of kadakkodies.