Haematologic malignancies such as acute and chronic leukaemias rarely present with or develop pleural effusion during their clinical course. We present a case of a young female who presented with unilateral pleural effusion and was diagnosed with haematologic malignancy on pleural fluid cytology. On further workup, a diagnosis of acute myeloid leukaemia was established. The patient was put on chemotherapy thereafter. This case clearly highlights the importance of cytopathology aids in making a diagnosis of rare and unusual presentation in haematologic malignancies.