Extensive ground surveys and patrolling trips were made along the sandy beaches of Karachi coast, Sindh for a period of 19 years (1979 – 1997) to study nesting grounds, nesting frequency and nesting season of green turtle (Chelonia mydas) and olive ridley (Lepeidochelys olivacea). The number of nests made in a month by green turtle ranged from 13 (May) to 197 (September) whereas that of Olive ridley varied from 1 (March & May) to 19 (August). The nests of olive ridley are shallower than those of green turtle. Nesting of green turtle occurred throughout the year with peak in September (20.82 %). Nesting of olive ridley was observed during June to August with peak in August (49.7 %). Nesting was inversely proportional to tidal level and water temperature. Intensity of nest forming in green turtles was markedly less during the first six months of the year compared to last six months. Arribada or mass nesting was not observed on the coast of Sindh.
