AIM: Recent surgical de-escalation of the axilla in breast cancer management has led to reduced number of immediate and delayed axillary lymph node dissections (ALND) after sentinel lymph node biopsies (SLNBs). We aim to assess the postoperative impact of SLNB versus immediate and delayed ALND on arm lymphoedema and morbidity. METHODS: A retrospective analysis from a prospectively collected institutional database was performed reviewing the rates of lymphoedema and arm morbidity in terms of shoulder restriction and patient-reported functional deficit in women undergoing axillary surgery for breast cancer between 2013 and 2018. RESULTS: In this 776 patient cohort (564 SLNBs, 192 immediate ALNDs and 20 delayed ALNDs), at 12 months after surgery, the results are as follows: lymphoedema rate: SLNB (4.62%), immediate ALND (19.51%), delayed ALND (15.00%); axillary cording rate: SLNB (3.08%), immediate ALND (10.65%), delayed ALND (5.00%); new functional deficit: SLNB (5.58%), immediate ALND (13.66%) and delayed ALND (20%); pain SLNB (14.02%), immediate ALND (15.97%), delayed ALND (17.65%); shoulder flexion/abduction restrictions: SLNB (8.14%/5.14%), immediate ALND (16.45%/15.79%) and delayed ALND (17.65%/20.00%). ALND was associated with increased risk of developing lymphoedema, shoulder dysfunction and development of more than one morbidity. No statistically significant difference in lymphoedema and morbidity outcome was observed between immediate and delayed ALND. CONCLUSION: Immediate and delayed ALND have comparable outcomes, but both are associated with increased postoperative arm lymphoedema and morbidity outcomes compared to SLNB alone. Preoperative appropriate selection of patients for axillary surgery treatment may improve lymphoedema outcomes in breast cancer patients.