The interaction between iodine and AOT in reversed micelle solutions of AOT in (n)-hexane is reported. The absorption spectrum of iodine exhibits two bands in (n)-hexane: (\lambda_{\max }=\mathbf{5 2 0}) and (290 \mathrm{~nm}). When AOT is added a new absorption band appears at (385 \mathrm{~nm}). This band shifts hypsochromically and its intensity increases when the surfactant concentration is increased. The intensity of the (290-\mathrm{nm}) band also increases while that of the (520-\mathrm{nm}) band decreases. The existence of an isosbestic point at (488 \mathrm{~nm}) may indicate an equilibrium between the iodine and the surfactant. When water is added to AOT- (I_{2}) solution in (n)-hexane the (\lambda_{\max }) of the band at (380 \mathrm{~nm}) at (W=0) shifts to (360 \mathrm{~nm}) at (W) (=15), while its intensity dramatically decreases. Also, the band intensity at (290 \mathrm{~nm}) decreases while that at (520 \mathrm{~nm}) increases. The isosbestic point observed without water is maintained. Thus, water seems to decrease the magnitude of the interaction observed on increasing [ (\Lambda \mathrm{OT}]). These results are interpreted in terms of the formation of electron donor-acceptor complexes between (\mathrm{OO}^{\prime} \mathrm{T}) and (\mathrm{I}{2}). A strong (1: 1) outer complex that develops in a 1:2 inner complex depending on the relative concentrations of (\mathbf{I}{2}) and AOT micelles is proposed. Both complexes seem to be formed at the micelle interface, showing a microenvironment polarity dependency. The changes are much more significant in the micelle domain ( at (W<10) ) than in the microemulsion domain. This interaction has been quantified as a function of (W) and AOT concentration. (9) 1994 Academic Press, Inc.