Differential cross sections for (p, α) reactions at Ep = 38 MeV have been obtained for 9Be, 11B, 12C, 16O and 19F. Some angular distributions show a well-developed diffraction pattern, others do not. The results have been compared with PWBA calculations for four direct mechanisms (pick-up, knock-out, heavy-particle pick-up and heavy-particle knock-out). No single mechanism seems able to reproduce the pattern of any observed distribution for the whole angular range investigated. © 1969.