Semi-empirical systematics of (p,alpha) (p,n alpha), and (p,np) reaction cross-sections were obtained at various incident proton energies from 17.9 to 28.5 MeV. Systematics are based on analytical formulas derived using the pre-equilibrium exciton model, evaporation model and semi-empirical mass formula. Parameters of systematics were fitted to the data obtained from the analysis of available measured crosssections for (p,a) (p,na), and (p,np) reactions. (c) 2007 Elsevier Ltd. All rights reserved.