We present a comparison between the average radio pulse profiles of millisecond pulsars (MSPs) in the field and in globular clusters. Our sample consists of 20 field MSPs and 25 cluster MSPs for which observations exist at 400 - 600 MHz.
We find that 6 of the 20 field MSPs, or about 30%, have a comparable interpulse at a phase offset of 180 ±30 degrees. None of the cluster objects shows this feature. Here we define a ‘comparable interpulse’ as one whose intensity is at least 10% of the primary pulse. This lower limit is well above the noise level of all the profiles in our sample. While the cluster MSPs have much more poorly resolved profiles at present than field MSPs, it is unlikely that a strong interpulse near 180 degrees could be ‘hidden’ within the primary peak.