Adult T‐cell leukaemia (ATL) is a mature T cell malignancy that is peculiar in its pathogenesis due to its association with the human T‐cell lymphotropic virus, HTLV‐I infection. The common manifestation of ATL is as leukaemia in 75% of cases and as pure lymphoma in the rest. The disease outcome of ATL is poor since treatment response is generally poor or partial and short lived in most patients. ATL, almost always occurs in adults with average age affected being the mid‐60s with no gender Predilection. Presence of atypical T lymphoid cells known as the flower cells is pathognomonic of the disease. Other diagnostic tests such as bone marrow examination and lymph node histology are indistinguishable from other peripheral T cell lymphomas. Immunophenotyping is often inconclusive and non-specific. Molecular testing for HTLV-1 is available only in selected research institutions and hence remains inaccessible to many. The above said difficulties lead to difficulty in identifying ATL cases. We present a case of ATL with a brief literature review, emphasizing the importance of recognising flower cells in peripheral blood smear.