Larval habitats of Armigeres subalbatus were delineated in urban and rural areas of Pondicherry. Survey of various potential mosquito breeding habitats revealed that septic tanks were the typical breeding habitat in both areas and the proportion was significantly higher in urban areas. The productive status of septic tanks differed in different months and the overall proportion breeding Ar. subalbatus was significantly higher in urban areas (0.0447) compared to rural areas (0.0181). Sporadic breeding observed in receptacles holding water admixed with cow-dung, was however insignificant. Among the various physico-chemical factors of septic tank habitat analysed in relation to breeding, only ammonia nitrogen was found to be significantly correlated with immature density.