We have reported the retardation of solvation dynamics of Coumarin 480 (C-480) in the Stem layer of the cetyltrimethylammonium bromide (CTAB)-sodium deoxycholate (NaDC) and Tween 80-NaDC mixed micelles compared to pure water using picosecond time-resolved emission spectroscopy. The slow solvation dynamics in the Stern layer of the mixed micelles is due to the water molecules confined in the Stern layer, counterions, and interactions of the counterions with the headgroups of the surfactant. The rotational relaxation time of C-480 in these mixed micelles is also investigated. The rotational relaxation times are retarded in the Stern layer of the mixed micelles.