A nanocolloidal dispersion of lead chromate (PbCrO4) has been prepared in H2O/sodium bis(2-ethylhexyl)-sulfosuccinate (AOT)/n-heptane water-in-oil (w/o) microemulsion medium. The formation of the PbCrO4 in the water pool of the microemulsion has been established by Fourier transform infrared measurements. The absorbance and fluorescence behaviors of the colloidal PbCrO4 have been investigated with varying water pool size, i.e., varying [water]/[AOT] mole ratio, omega. The dimension of the lead chromate encapsulated microemulsion droplets has also been determined by the dynamic light scattering method under varied w. The dimension and shape of the colloidal dispersions in microemulsion have been examined by transmission and scanning electron microscopic measurements.