To establish dosimetric predictors of radiation esophagitis (RE) in patients treated with a combination of carboplatin, paclitaxel, and radiotherapy. Three-dimensional radiotherapy plans of 26 patients with non-small-cell lung cancer who received 50-60 Gy of radiotherapy concurrently with weekly administration of carboplatin (AUC 2) and paclitaxel (40-45 mg/m(2)) were reviewed in conjunction with RE. The factors analyzed included the following: percentages of organ volumes receiving >40 Gy (V40), >45 Gy (V45), >50 Gy (V50), and >55 Gy (V55); the length of esophagus (total circumference) treated with >40 Gy (LETT40), >45 Gy (LETT45), >50 Gy (LETT50), and >55 Gy (LETT55); the maximum dose in the esophagus (Dmax); and the mean dose in the esophagus (Dmean). Data were obtained on the basis of superposition algorithm. All factors except Dmax showed statistical correlation with RE. Good correlations were shown between RE and LETT45 (rho = 0.714) and V45 (rho = 0.686). LETT45 and V45 appear to be useful dosimetric predictors of RE. It is also suggested that Dmax does not predict RE.