Introduction: Glycoconjugates are a class of glycoproteins or glycolipids, their terminal sugars are responsible for cell-cell and/or cell-extracellular matrix interactions. Aberrant glycosylation of these compounds are one of the most important aspects of cellular transformation, metastasis and escape of tumoral cells from immune system and resistance to antineoplastic drugs. Recent studies showed that patients with HPA (helix pomatia agglutinin) positive intraductal carcinoma cells have worse prognosis compared to patients with HPA negative cells. The aim of the present study was to define the presence of GalNac terminal sugar in glycoconjugate of different grades of intraductal breast carcinoma and to compare the degree and the pattern of reactivity of tumoral cells to HPA lectin. Materials and Methods: The paraffin blocks belonging to 20 patients of intraductal carcinoma was chosen from pathology archive of Khatam-Al-Anbia hospital in Zahedan and 5-7 micrometer sections were prepared. Two expert pathologists determined histopathological grading independently. The lectin histochemistry was performed using HPA. The same observers determined histochemical grading. Data were analyzed by NPAR (non-parametric) test of Mann Whitney. Results: Results of this study revealed that the pattern and the degree of histochemical reactivity of neoplastic cells differ in all grades of intraductal carcinoma. Histochemical staining showed significant difference between grades of intraductal carcinoma of the breast (p<0.003). The lowest reactivity was seen in grade I and the highest in grade III. Furthermore, the reaction of tumoral cells was primarily confined to apical surfaces of cells in grade I, to the Golgi zone in grade II, and to a diffuse cytoplasmic distribution in grade III. Conclusion: Our data suggest that the HPA reactivity of tumoral cells were different in all grades of intraductal carcinoma. The tumor cells showed aberrant glycosylation, which occurred in the course of anaplastic changes. It seems that our data suggest a potential and clinically important role of HPA reactivity to predict the invasive nature of malignant tumoral cells of intraductal carcinoma of the breast.