Excitation functions for the reactions 89 Y (p, n)89g Zr and 89 Y (p, n)89m Zr have been measured over the energy ranges from threshold to 15 MeV using stacked foil activation technique. The isomeric cross-section ratio σm/(σm+σg) for the formation of 89m, g Zr was determined. The excitation functions and isomeric cross-section ratios were calculated for the reactions 89 Y (p, γ)90m, g Zr , 89 Y (p, n)89m, g Zr , 89 Y (p, p)89m, g Y and 89 Y (p, αn)85m, g Sr also for energy range 4–40 MeV . The PE emission fraction is found to depend strongly on the energy of the incident particle. The isomeric cross-section ratio is found to depend strongly on the relative spins of the isomeric and ground state and some dependence on energy difference between the levels.