This study compared the intra- and inter-examiner measurement error of the Florida Probe, Florida Disk Probe, and conventional periodontal probe in persons having moderate to severe periodontitis. Single pass measurements using the conventional probe were compared to both single and double pass (corrected) measurements using the Florida Probe and Florida Disk Probe. The mean intra-examiner standard deviations of differences in repeated site probing depth measurements ranged from 0.60 to 0.93 mm for the Florida Probe and from 0.52 to 0.89 mm for the conventional probe. Based on overall averages, the conventional probe measured deeper probing depths than the Florida Probe at the same sites. This difference was especially evident in pockets greater than or equal to 6 mm in depth. Based on sites, the mean intra-examiner standard deviations of differences in repeated relative attachment level measurements using the Florida Disk Probe ranged from 0.55 to 0.82 mm. The mean standard deviations of site measurements for attachment level obtained with the conventional probe ranged from 0.62 to 1.14 mm. Inter-examiner measurement error was greater than intra-examiner measurement error for each probing method. It was concluded that use of the Florida Probe and Florida Disk Probe may offer significant advantages in reducing measurement error for some clinical examiners. For other examiners, use of the Florida Probes do not necessarily result in less measurement error than use of conventional probing methods.