A final-state wavefunction, involving three appropriate confluent hypergeometric functions, which satisfies the correct asymptotic condition is used to study positron-impact ionization of atomic hydrogen. Results are reported for the double as well as triple differential cross sections and compared with the available theoretical findings. The double differential cross section curves for different ejection angles show the presence of a cusp-like structure at the region of equal energy sharing by the outgoing positron and the ejected electron. This is in conformity with the findings of Mandal et al. (1986) at zero ejection angle but unlike the structure exhibited by the curves of Schultz and Reinhold (1990).