Gastrin has a trophic effect on the mucosa of the gastrointestinal tract and seems to have the potential for promoting colonic cancerogenesis through a chronic stimulation of the epithelial proliferation. Plasma gastrin has been reported to be elevated in patients with colorectal neoplasms. The aim of the present study was to verify this observation. Presurgical serum levels of gastrin were compared between 49 patients with colorectal neoplasms and 47 controls hospitalized for other surgical lesions. Results show significantly higher gastrin levels of case group than controls: 72.72 + 85.41 vs. 46.79 + 24.09 pg/ml (p < 0.05), and provide support for the hypothesis of a gastrin-stimulated neoplastic growth enhancing at the same time the potential therapeutic role of reducing gastrin secretion.