We studied the breeding biology of Purple Swamphens (Porphyrio porphyrio poliocephalus) at Nainar Pond in Tirunelveli, South India from January 2003 to May 2004. Peak breeding activity occurred from the second week of January to the first week of March. Nests were built on thick floating vegetation closest to the bank of the pond. Nesting material consisted of whole plants, stems, and leaves of Eichhornia crassipes, Jussieua repens, Pistia stratiotes, Ipomoea aquatica, and Cyperus rotundus with E. crassipes being most preferred. Nest dimensions were variable. Clutch size varied from three to seven eggs with a mean (± SD) clutch size of 4.5 ± 1.5 and a model clutch size of four eggs. Mean volume of all eggs was 32.3 ± 3.5 cm³. The length of the incubation period was estimated as 19.8 ± 1.2 days. Nest and egg hatching success were estimated as 80.0% and 61.1%, respectively, while overall fledging success was 42.0%.