BACKGROUND: Sentinel lymph node (SLN) biopsy may improve nodal staging in cervical cancer. The aims of this study are to determine the rate of unusual patterns of cervical lymphatic drainage, to determine the rates of micrometastases and isolated tumor cells (ITCs) in SLNs, and to assess the clinical impact of SLN biopsy. METHODS: Multicenter prospective study conducted between January 2005 and June 2007 in women undergoing laparoscopic surgery for early cervical cancer. Combined technetium/Patent Blue labeling was used. Lymphoscintigraphy was performed before surgery. SLN location was recorded, and factors associated with location were explored. SLNs underwent step sectioning +/- immunohistochemistry. RESULTS: 145 patients were enrolled and 139 included in a modified intention-to-diagnose analysis. Although 80.6 % of SLNs were in external iliac and interiliac areas, 38.2 % of patients had at least one SLN in an unexpected area and 5.1 % had SLNs only in unexpected areas. In unexpected areas, the number of SLNs per patient was not significantly different between lymphoscintigraphy and intraoperative detection (0.79 [0.62-1.02] versus 0.50 [0.37-0.68]; P = 0.096). In expected locations, there were significantly more blue and hot SLNs per patient than blue or hot SLNs (1.70 [1.45-1.99], 0.42 [0.30-0.57], 0.52 [0.39-0.69]). Of 28 metastatic SLNs, 17 contained micrometastases or ITCs. SLN involvement was found only by immunohistochemistry in 39.1 % of patients with positive nodes, and involved SLNs were located in unexpected areas in 17 % of those patients. CONCLUSIONS: Sentinel lymph node biopsy detects unusual drainage pathways and micrometastases in a substantial proportion of patients, thus improving nodal staging.