Community participation has become an ambiguous umbrella term under which a huge diversity of practices may occur, ranging from 'true' participation to the rhetorical participation, which serves merely to legitimize external interests in a development project. One variable within the participation process that may differ enormously is that of who participates. The tendency to assume that communities are homogenous entities has meant that many people within the community have been excluded from participating. The first section describes some determinants of who participates, which include socio-economic and socio-cultural factors. The remainder of the paper focuses draws on the case study of a rural development project undertaken in a Guatemalan Mayan Community. The local environment and history are described followed by characteristics of the participants, including an exploration of the characteristics of the project staff. The author concludes that participation in voluntary community development projects is largely dependent on socio-economic factors. In addition, geographical access, external social links, age, personality and cultural values all played a part in distinguishing who participates.