The presence of serum cold agglutinin can be the initial presentation of lymphoproliferative diseases. Conditions with persistent cold agglutinins are a spectrum of diseases that vary from benign lymphoproliferation of the "autoimmune-like chronic cold agglutinin disease" to malignant lymphoma. We report a case of a 72-year-old woman who presented with severe anaemia, hepatosplenomegaly and episodes of peripheral haemagglutination precipitated by cold exposure. The haemoglobin was 5.6 g/dL with a cold agglutinin titer of 1:256 at 4 degrees C and 1:8 at room temperature (30 degrees C). The cold agglutinin showed anti-I specificity and kappa light chain restriction. Peripheral blood showed atypical lymphoid cells with a B-cell immunophenotype. Immunoglobulin gene rearrangement study by polymerase chain reaction (PCR) showed an amplified band at 100 bp, consistent with a clonal proliferation of B-lymphocytes. We believe that our patient had cold antibody haemolytic anaemia as the initial presentation of a low-grade non-Hodgkin's lymphoma. The association of cold antibody haemolytic anaemia with low-grade B-cell lymphoma is unusual.