The feeding, burrowing and fighting behaviour and courtship display of the two ocypodids Heloecius cordiformis (H. Milne Edwards) and Hemiplax latifrons (Haswell) are described from daytime observations in the field over a two-year period and from four months study under laboratory conditions. The behaviour of the two species is compared with that of other ocypodid crabs. Heloecius cordiformis and Hemiplax latifrons live intertidally in estuaries in semi-permanent burrows and feed on detritus sifted from the mud and sand by the mouth-parts. The two species each possess considerably stereotyped patterns of behaviour, particularly in relation to fighting and courtship display in which the two differ most. The courtship display of Heloecius cordiformis closely resembles that of vertically waving, narrow-fronted species of fiddler crabs (genus Uca). The fighting behaviour of Hemiplax latifrons is similar to that of the New Zealand Hemiplax hirtipes (Jacquinot) which apparently lacks courtship display.