Compositions in the (1-x)LaAlO3-xTiO(2) system were prepared in order to modify the negative temperature coefficient of the resonant frequency (tau(f)) of LaAlO3. The microwave dielectric properties and phases of these compositions were investigated. X-ray powder diffraction results showed that LaAlO3 and TiO2 form a solid solution in the composition range from x = 0 to x 0.6. The dielectric properties of the (1-x)LaAlO3-xTiO(2) system exhibit nonmonotonic behavior with compositions. The low permittivity and negative tau(f) of LaAlO3 appear to dominate the dielectric properties of the (1-x)LaAlO3-xTiO(2) system for TiO2 concentrations as large as 60%.