Monte Carlo caluculations of electron collisions on highly excited hydrogen atoms K.Kawakami, A.Tanaka, T.Imaida and T.Fujimoto Department of Engineering Physics and Mechanics, Kyoto University We have examined cross sections for ml-changing, l-changing, and n-changing transitions and for ionization in the semiclassical approximation. Cross section values are compared with the semiempirical formulas. Excitation cross sections continue smoothly to the "ionization cross section". For ionization the relative angle of the two outgoing electrons is larger than 90 degrees.