Esophageal cancer (EC) accounts for a considerable proportion of carcinomas of the upper gastrointestinal tract in the population of the Caspian littoral. The global histologic pattern of the disease has changed recently. The intent of this study was to determine the incidence of EC over the past decade in Eastern Azerbaijan--a north-western province of Iran--on the western side of the Caspian littoral and to assess the alteration of the histological pattern of the disease. In a retrospective study, all 1792 documented EC cases of all registered cancer, surgery, pathology, and radiotherapy centers of the province over a period of 9 years (from March 1994 to March 2003) were enrolled in the study. Data concerning demographic characteristics, EC risk factors, and histological findings were recorded. The incidence and the relative incidence of the pathological subtypes of EC in the population of the province were determined. The change in incidence rates and the interaction between main risk factors and tumor histology of the patients were assessed over the study years. The average incidence of EC in the over 30-year-old population of the province was 16.2 (12.7 for squamous cell carcinoma [SCC] and 1.9 for adenocarcinoma [AC]) cases per 100 000 person-years. Incidence of SCC, as well as AC, peaked at ages older than 65. Compared to women, men had higher incidences of AC and lower incidences of SCC; the average incidence rate of EC was equal in men and women. AC and SCC accounted for 12.8% and 86.9% of cases, respectively. Upper, middle and lower thirds of the esophagus were the location of tumors in 9.8%, 32.9% and 57.3% of cases, respectively. During the study period, incidence rates of EC and SCC tended to decrease. The incidence rate of EC from 1995 to 1998 was almost 30% higher than that of the period from 1999 to 2002. Incidence rate of EC on the western side of the Caspian littoral is moderately high, but much lower than that of the eastern Caspian littoral as it was three decades ago. The incidence of EC was lower in the second half than the first half of the study period. Unlike the global pattern of EC, the incidence of EC as well as SCC in women is as high as or higher than in men, which is identical to the pattern in the eastern Caspian littoral.