Tributylphosphine oxide is proposed as an extractant for uranium(VI) and thorium(IV) from salicylate media. The optimum extraction conditions were evaluated by studying various parameters such as pH, sodium salicylate concentration, tributylphosphine oxide concentration, diluents and shaking time. The extracted species were ascertained by logD-logC plots. The method is simple, fast, precise and permits the separation of uranium(VI) and thorium(IV) in binary as well as multicomponent systems. The method is also applied for the determination of uranium(VI) and thorium(IV) in monazite sand samples.