Background/Aim. Conventional axillary dissection in breast cancer surgery implicates the section of the neurovascular elements passing through the dissected tissue: the intercostobrachial nerve (ICBN) and lateral thoracic vein (LTV). Preservation of the ICBN during axillary dissection is well documented in the literature, with slightly contradictory results of its influence to postoperative pain. There is no published data, as far as we know, on the functional effects of preserving the LTV. We supposed that ligation of the LTV contributes to the emergence of postoperative breast edema, which is common in breast cancer conservative surgery. The preservation of venous drainage could diminish the frequency of this undesired occurrence. Methods. In a prospective study, 126 patients undergoing axillary node clearance for breast cancer of stages I and II were randomly selected for preservation of ICBN and LTV (n = 65), or for conventional dissection (n = 61). Sensory deficit, pain and breast edema as a dichotomized characteristics were examined in the first two weeks after the surgery. Results. No difference in the number of dissected nodes was seen between the two groups (p = 0.7). The loss of sensitivity was significantly less common in the group randomized for ICBN preservation (16/65 vs. 30/61, p < 0.005), while there was no difference in the pain intensity and duration (49/65 vs 44/61, p > 0.05). LTV was preserved in 22 patients in the group for preservation, and in none of the control group. Breast edema was registered in 33 patients from the group for preservation (51%) and in 37 patients from the control group (61%). The difference in distribution was not significant, and the same results were obtained when the frequency of breast edema in the group with preserved LTV (22 patients, 10 of them without breast edema) was compared with the all others (p > 0.05). Conclusion. The preservation of the ICBN significantly improved the functional effect of the axillary dissection for breast cancer by reducing sensory loss, while there was no difference in pain intensity and duration. Although we did not prove that the preservation of LTV prevents breast edema after conservative surgery for breast cancer, we think that more complex analysis, including parameters such as the extent of resection of breast tissue, the dimension and constitutional characteristics of the breast, tumor location, obesity, and further developments in surgical technique, would reveal at least discrete improvements in the functional results of this surgical approach.