C-reactive protein (CRP) is a sensitive marker of inflammation in a variety of diseases, particularly in rheumatoid arthritis (RA). This study examines whether CRP levels are associated with increased risk of developing RA in healthy women. Study participants were from the Women's Health Study, a completed randomized trial of aspirin and vitamin E in cardiovascular disease and cancer prevention, begun in 1992. After 9.9 years of follow-up, 398 women reported a new diagnosis of RA, of which 90 cases were confirmed. In analyses adjusting for the risk factors, age, body mass index, and smoking, there was no increased risk of developing RA when measuring CRP at a single point in time. On whether CRP levels predicted incident RA within 4, from 5 to 8, or more than 9 years of CRP measurement, no significant associations for any period were found. In conclusion, a single CRP level did not predict increased risk of RA. Furthermore, CRP measurement closer to the time of diagnosis was not predictive. The consistency of this effect throughout different periods from diagnosis suggests that CRP does not have a large effect in predicting incident RA.