Granulocyte colony-stimulating factor (GCSF) is a recombinant human growth factor widely used in haematology. It is known to cause cutaneous vasculitis and neutrophilic dermatoses. We present three cases of Sweet's syndrome (SS) associated with GCSF use. Raised GCSF levels have been demonstrated in patients with SS. GCSF is the best understood mechanism by which neutrophil accumulation occurs and shows a dose-dependent effect in provoking SS.