AIMS--The purpose of this study was to examine whether preoperative activity of rheumatoid arthritis influences the extent of anterior chamber inflammation after cataract extraction and intraocular lens implantation. METHODS--The medical records of 23 consecutive patients (33 eyes) with rheumatoid arthritis, who underwent cataract extraction with intraocular lens implantation, were reviewed during a 4 year period from April 1990 to March 1994. RESULTS--Eleven patients who still showed a 1+ level of aqueous cells 1 month after the surgery had significantly higher titres of rheumatoid factor preoperatively, compared with the other 12 patients who showed no aqueous cells (p = 0.0019, Mann-Whitney U test). The persistence of aqueous cells also had a significant correlation with extracapsular cataract extraction compared with phacoemulsification (p = 0.0391, chi 2 test). Multivariate analysis showed that the titre of rheumatoid factor was the more significant element to determine the persistent aqueous inflammation. All the eyes, except for four which had a macular hole, optic disc atrophy, or retinitis pigmentosa gained visual acuity of 20/30 or better. The aqueous cells cleared 3 months after the surgery and left no complications in any of the eyes. CONCLUSION--Intraocular lens implantation is basically a safe procedure for patients with rheumatoid arthritis, although postoperative aqueous inflammation tends to be persistent in patients with high titres of rheumatoid factor.