During industrialization in agriculture, many farming machines have been introduced. It is well-known that farming is a dangerous workplace and that farm machinery cause many serious accidents every year. Four cases of accidents with potato harvesters are discussed. In three of four cases the farmers were injured while cleaning the machine without stopping it, which probably was the main cause of the accidents. Farmers are in general not careful enough when using farm machinery. Every year, farmers in Denmark are severely invalided in accidents with potato harvesters. A strategy to lower the accidents is proposed: 1. Information of farmers, farmer schools, machine constructors and importers about mechanisms of injury. 2. A better education of farmers in using potato harvesters (and other farming machines). 3. Better fencing of the potato harvesters. 4. If possibly constructional changes in the potato harvesters so things will not get stuck, or so that the machine will stop if things stuck. 5. Installation of switches on potato harvesters, which can be reached from all positions, stopping the machines immediately, or a remote switch control carried by the farmer.