Despite improved results gained by the combination of neoadjuvant chemotherapy and radiotherapy with surgery, the prognosis for the esophageal carcinoma patient remains poor. There is a need for prognostic markers that can help improve patient selection. The aim of this study was to evaluate whether serum levels of C-reactive protein (CRP) have any influence on the patient prognosis in terms of prediction of chemoradiosensibility, and overall and disease-free survival. Blood samples were obtained at the time of diagnosis in 67 patients with biopsy-proven primary carcinoma of the esophagus. Although not significantly, the mean CRP level was higher than that of 20 patients with benign esophageal pathology who served as controls. No significant correlation could be found between CRP levels and baseline characteristics such as age, gender, histology, cancer localization, tumor depth, lymph node status or metastatic spread. However, patients with CRP levels higher than 6 mg/L were more frequently non-responders to chemoradiotherapy (P = 0.035), had a shorter overall survival (P = 0.061) and a shorter disease-free survival (P = 0.016). It is concluded from these results that pretreatment measurement of serum CRP levels in patients with esophageal cancer could to be used in routine practice as indicators of chemoradiosensibility and prognosis.