Myelopathy is a well recognised but rare association with Mycobacterium tuberculosis infection, but has not been described with atypical mycobacteria. We report two cases of disabling myelopathy in association with pulmonary infection by Mycobacterium kansasii and Mycobacterium malmoense; the myelopathy is presumed to be a para-infectious phenomenon. (Thorax 2001;56:158-160 A 23 year old, right handed computer operator with type 1 diabetes mellitus presented with a four month history of weight loss, productive cough, increasing breathlessness, and a one day history of chest pain. On examination the only abnormalities were coarse inspiratory crackles in both upper zones of the chest and some tenderness to the right of the T8 spinous process. Routine biochemical and haematological investigations were normal. Chest radiography showed multiple, bilateral, thin walled cavities in the upper zones. Ziehl-Neilson staining of the sputum confirmed the presence of acid and alcohol fast bacilli. HIV antibody test was negative. Treatment was started with rifampicin, isoniazid, and pyrazinamide.