In this article, J.St.Mill's philosophy of mathematics is presented and discussed. First, Mill's views concerning geometry (which - in his opinion - is a general science concerning physical space) is presented. Knowledge of geometrical principles is obtained via inductive generalizations of our observations of physical phenomena. A short discussion follows whose conclusion is that Mill's explanation of the nature of geometrical knowledge is not satisfactory. Nevertheless, his ideas are of certain importance in the philosophy of mathematics, as Mill can be considered a predecessor of the quasi-empiricist philosophy of mathematics of Putnam and Quine.