Single phase, (100) oriented Ba0.5Sr0.5TiO3 films have been deposited by pulsed laser deposition onto (100) LaAIO3, SrTiO3, MgO substrates. The dielectric properties of these films were measured using interdigitated capacitors as a function of DC bias and temperature at 1 MHz and as a function of DC bias at 1 to 20 GHz at room temperature. Deposited films were annealed over a temperature range of 900 to 1350 C for 1 to 8 hours to observe its effect on dielectric properties. Chemical analysis on films deposited from stoichiometric targets showed the films to be up to 6% deficient in Ba and Sr under typical PLD deposition conditions. Optimal annealing conditions and target stoichiometries for minimizing dielectric loss and maximizing tuning are discussed.