Objectives– Although there is growing evidence for a relation between Parkinson syndrome (PS) and mitochondriopathy (MCP), little is known about the frequency of PS in MCP. Material and methods– This study assessed the frequency of PS in patients with MCP, the phenotype of these patients, and their response to anti‐Parkinson medication, during a 1‐year period. Results– Between April 1999 and March 2000 PS was diagnosed in nine of 76 patients with MCP (12%). The frequency of MCP among 144 patients with PS attending the department during the investigational period was 6.3%. Systems most frequently affected by the MCP in the nine patients were the peripheral nervous system, central nervous system, endocrinium, heart, intestines, eyes, ears and kidneys. PS in MCPs responded well to amantadine, L‐DOPA, dopamine agonists and catechole‐o‐methyl‐transferase inhibitors. Conclusion– Twelve per cent of the patients with MCP have phenotypic features of PS and 6% of the patients with PS have features of MCP. MCP patients with PS frequently show multisystem involvement. PS in MCP responds well to anti‐Parkinson medication.