Mean pulse polarization properties at 1.4, 4.6, and 8.3 GHz and rotation measures are presented for two pulsars with unusually wide profiles. PSR J0437-4715 is a millisecond pulsar with significant emission over at least 80% of the pulse period. It shows a complicated variation of linear position angle across the pulse indicating substantial departures from a dipole field structure. PSR B1259-63, which has a pulse period of 47.7 ms, has a mean pulse profile with two components of almost equal amplitude separated by 140 deg of longitude. Both components are more than 80% linearly polarized and there is an approximately constant gradient of position angle across them. The observed position angles are well represented by the rotating vector model, with the implication that the minimum angle between the rotating vector and the line of sight occurs in the wider gap between the components.