There are few reports confirming the validity of sentinel lymph biopsy in patients with a background of lymphoproliferative disease. We reviewed nine cases of women who underwent sentinel lymph node (SLN) surgery for staging of primary breast cancer with a diagnosis of lymphoproliferative disease. SLN identification rate was 100 per cent with a background of lymphoma in the sentinel node in eight of the nine patients. With a mean follow-up of 37 months, there have been no axillary recurrences in any of these patients. These cases illustrate that SLN staging is feasible and provides axillary staging information in women with breast cancer despite synchronous lymphoproliferative disease.