Mediastinal masses present challenging problems in thoracic practice. Most of them remain asymptomatic for long and by the time the pressure symptoms develop, these are quite advanced. Carcinoids arising from the mediastinum are invariably related to thymus. Non-thymic origin of mediastinal carcinoids is rare, especially in the posterior mediastinum. Only two cases of posterior mediastinal carcinoids have been reported so far. These were assumed to be arising from ectopic thymus tissue. We report a case of a 45-year-old woman who presented with dyspnoea and dry cough due to giant carcinoid tumour of the mediastinum, the pedicle originating from the posterior mediastinum, not related to thymus. She underwent thoracotomy and resection that provided relief. The immunochemical studies revealed positive reaction to cytokeratin, chromogranins and synaptophysin, and negative reaction to S100, CD99 (MIC2) confirming the tumour being neuroendocrine in nature.