Lymphedema of the upper extremity, in addition to being unsightly, can be painful, can limit the arm movements, increases the risk of infection and is psychologically distressing, serving as a constant reminder of cancer. 1. To ascertain the incidence of lymphedema in a hospital based population (in patients undergoing axillary dissection for breast cancer. 2. To determine the clinicoepidemilogical factors associated with the occurrence of lymphedema in these patients. For all patients undergoing axillary dissection, arm measurements were taken in the pre-& post-operative period from at least 3 sites; one in the arm, forearm and wrist (points fixed in reference to fixed bony landmarks). Patients included in this study were followed up for at least 12 months. Circumference difference of more than 5% was taken as mild lymphedema; more than 10% as moderate lymphedema and more than 15% as severe lymphedema. Data was analyzed using SPSS 11.0 statistical software. Of the 231 patients in this study mean age was 51.2 years, majority were housewives (71.9%) and postmenopausal (58.5%). Modified radical mastectomy (MRM), was performed on 203 (87.9%) patients. 57.2% patients had positive lymph nodes. The mean number of positive nodes was 6.52. Majority of the patients received chemo and radio therapy. Overall incidence of lymphedema was 41.1%. The definition of 5-10% increase as mild lymphedema may be a bit severe as in most patients with this increase, lymphedema is not clinically apparent. The incidence of moderate and severe lymphedema in our series is only 7.4%. The incidence of clinically significant lymphedema (moderate to severe lymphedema & symptomatic mild lymphedema) was 16.8%. Only axillary irradiation and pathological nodal status (pN3) emerged as significant risk factors for lymphedema development on multivariate analysis. Lymphedema once established is difficult to treat. Combination of axillary dissection with radiation and more nodal positivity seems to predispose to lymphedema. Prevention by means of sentinel node biopsy in early cases, good surgical technique, arm care post surgery, exercises and massage therapy may help reducing the incidence and/or severity.