Sol-gel technique was used to prepare thin films of CdS microcrystallite doped SiO 2/TiO 2 glass onto soda lime glass substrates. Ti(OBu 4), TEOS and Cd(CH 3COO) 2 were used as starting material for preparation of SiO 2/TiO 2 films in the attempt to optimize both thickness and optical properties. Thioacetamide and thiourea were used as internal source of sulfur to transform the Cd(CH 3COO) 2 into CdS to enhance nonlinear optical behaviors. The presence of the CdS microcrystallites in the films was verfied by using Raman spectroscopy. The evidence of size effects was apparent from the absorption spectrum of the thin films. The nonlinear refraction and nonlinear absorption of the thin films were tested by Z scan technique.