The extracts of the prop roots of Pandanus fascicularis Lam (Family: Pandanaceae) is claimed as an antidiuretic by some traditional practitioners. However, the validity of this claim has not been scientifically proven or refuted. The aim of this study was to evaluate the antidiuretic potential of ethanol and aqueous extracts of prop roots of P. fascicularis in rats following oral administration. Ethanol and aqueous extracts were prepared from P. facicularis by percolation and cold maturation, respectively. Furosemide was used as a diuretic agent to induce diuresis. Vasopressin (ADH) was used as a standard. The results demonstrated both the ethanol and aqueous extracts of P. facicularis and ADH significantly impaired the total urine output. However, antidiuretic potential of ethanolic extract was similar to that of ADH. The extracts caused a significant decrease in natriuresis and kaliuresis. From this study, we can conclude that ethanol extract of prop roots of Pandanus fascicularis has beneficial effects on anti diuretic activity. It has the potential to impart therapeutic effect in diuretic.