Mycoplasma pneumoniae infection is no longer a benign condition it was originally thought to be. Many extrapulmonary manifestations affecting major organ systems like the central nervous system, cardiovascular system, haematological system, gastrointestinal system, musculoskeletal system and renal system have been described. Early recognition of these manifestations is often difficult and serological diagnosis may not be helpful. Three patients with large pleural effusions, encephalitis, hemiplegia, hepatitis, autoimmune haemolytic anaemia and renal failure are discussed to highlight the many varied presentations associated with this infection.