The carpus-to-digits distance measured on a posteroanterior roentgenogram of the hands and wrists takes into account 18 different joints. This study demonstrates that the carpus-to-digit distance is a simple, reproducible score which reliably reflects progression of roentgenological rheumatoid arthritis lesions and is correlated with Larsen's lesion score and with Steinbrocker's index, but not with Larsen's erosion score during the first two years after onset of the disease. Larsen's erosion score and similar parameters should be preferred for clinical studies of recent-onset rheumatoid arthritis. The carpus-to-digit distance, which requires neither a reference film not observer training, is appropriate for long-term clinical studies.