Nearly two million Dutch people suffer from more than one chronic disease (multimorbidity). This dissertation shows that treatment results in people with intermittent claudication are worse if they suffer from multimorbidity. Seventy per cent of physiotherapists do not apply disease-specific treatment guidelines if people suffer from multimorbidity. This is found to be favourable as physiotherapists in daily practice are shown to be more successful than those in controlled studies. When comparing similar patient populations (1.440 patients in clinical studies and 3.513 patients in regular physiotherapeutic care settings), the increase in walking distance after six months of supervised walking training turned out to be 25% higher in patients treated by physiotherapists in regular care settings.