Objective: Neoadjuvant chemoradiotherapy (NT) is standard procedure for locally advanced rectal cancer. In this study, we compared the morphology of lymph nodes and the amount of plasma cells in the interfollicular region of lymph nodes in rectal tumour surgical excision material, between two groups who had received and not received NT prior to surgery. Method: Fifty cases with NT and forty cases without NT were included. The number and diameter of lymph nodes were recorded. The morphology of the lymph nodes were evaluated, and the percentages of interfollicular plasma cells were demonstrated immunohistochemically (CD138). Tumor regression grade was assessed using Mandard scoring system. Results: Average number and diameter of lymph nodes were greater in patients without NT (p<0,05). Atrophy of germinal centers was noted as 54 % in NT group, versus 5 %. The amount of plasma cells in the interfollicular region was found to be higher than fifty-one percent in 54 % of NT group versus 5 % (p<0,05), as well. Complete response rate (Mandard's: 1) was 18 %. No significant association was found between the amount of plasma cells and tumor regression. Conclusion: NT leads to a decrease in the volume of the lymph nodes and atrophy of germinal centers, conversely, causes stimulation of the proliferation of interfollicular plasma cells.