The main purpose of this study is the investigation of a cross section of proton induced nuclear reactions. The excitation functions of the reactions: Fe-56(p,2n)Co-55 Fe-58(p,2n)Co-57, Cd-111(p,2n)In-110, Cd-112(p,2n)In-111, Te-125(p,2n)I-124, Te-126(p,2n)I-125, Zn-68(p,2n)Ga-67 were investigated. These reactions were studied as the resulting radioisotopes are used in medical applications. Theoretical excitation functions have been calculated with TALYS 1.6 nuclear reaction simulation code. The calculated excitation functions are compared with the experimental data.