The microstructural characteristics of water/AOT/isooctane microemulsions have been investigated by FT-IR spectroscopic technique. The broad peaks obtained for water OH and carbonyl bands have been resolved by Gaussian curve fitting, and the vibrational characteristics, particularly thepeak intensity and peak area corresponding to each peak, have been analyzed. It has been observed that the aqueous core of the microemulsion droplet is composed of bound and free water while a small amount of water remains trapped in the interface. The maximum hydration number of AOT was found to be 12. The phenomena of rotational isomerism of the AOT molecule reported earlier with other techniques have also been revisitedfrom the deconvoluted carbonyl bands of AOT molecule.