Oesophageal cancer is endemic in some regions of the Islamic Republic of Iran and efforts have made to find factors that play a role in its prognosis. We retrospectively examined the correlation of serum alkaline phosphatase (ALP) levels with several clinicopathological characteristics of 207 cases of oesophageal carcinoma. The mean ALP level in patients with lymph node involvement was significantly higher [141 (SD 77) U/L] than with node negative cancers [116 (SD 63) U/L]. Patients with ALP levels 165 U/L were 3.29 times more likely to have lymph node involvement than patients with ALP levels < or = 165 U/L. There was no statistically significant correlation between ALP level and sex, age, tumour histological type, site and size of tumour, depth of penetration, distant metastasis, degree of differentiation, presence of lymphatic invasion and presence of simultaneous multiple cancers. Elevated ALP in patients with oesophageal cancer may predict lymph node involvement.