We have calculated the contribution of order M π 5 in the chiral expansion of the nucleon mass in two-flavour heavy-baryon chiral perturbation theory. Only one irreducible two-loop integral enters, and this vanishes. All other corrections in the heavy-baryon limit can be absorbed in the physical pion-nucleon coupling constant which enters in the M π 3 , term, and so there are no contributions at M π 5 . Including finite nucleon mass corrections, the only contribution agrees with the expansion of the relativistic one-loop graph in powers of M π /m N , and is only 0.3% of the M π 3 term. This is an encouraging result for the convergence of two-flavour heavy-baryon chiral perturbation theory.