Objective: Lower limb lymphedema (LLL) is a major cause of morbidity in patients with gynecological malignancies after surgical treatment involving lymph node (LN) dissection. The aim of this study was to estimate the prevalence of LLL in such patients and detect risk factors for its occurrence. Materials and Methods: A retrospective analysis of all patients undergoing lymphadenectomy in newly-diagnosed gynecological malignancies at the University Hospital of Zurich between 2000 and 2007 was performed. Data from 313 patients were collected. Twenty patients with pre-existing edema or missing information were excluded before analysis. Time-to-LLL was estimated using the Kaplan-Meier estimate and potential risk factors were evaluated by a Cox regression model. Results: Estimated prevalence of LLL one year after surgery was 32%, increasing to 58% eight years after surgery. Median time to diagnosis of LLL was 5.2 years. The number of removed lymph nodes was significantly associated with time-to-LLL. Diagnosis of postoperative lymphocysts and local infections were accompanied by a significantly elevated risk for the development of LLL. Furthermore, time-to-LLL decreased with a higher body mass index (BMI) of the patient. In contrast, chemo- and radiotherapy, age, positive LNs, site of lymphadenectomy, and type of cancer were not observed to be associated with the occurrence of LLL. Conclusions: LLL is a frequent postoperative complication in patients undergoing lymphadenectomy for gynecological malignancies. It is thus imperative to sufficiently educate patients about the risk and symptoms of LLL prior to surgery. The data clearly show an association between time-to-LLL and number of dissected LNs, stressing the need to prospectively analyze the prevalence of LLL and carefully plan LN sampling as increasing knowledge is gained regarding the therapeutic benefit of sentinel and systemic lymphadenectomy in patients with different stages of gynecological malignancies.