There are a wide range of non-infectious disorders that can affect potatoes, generally as a result of imbalances within the plant caused by environmental stresses. Such disorders make tubers unappealing to consumers, and therefore have significant economic consequences. However, non-infectious disorders are often poorly understood and characterized, limiting the extent to which they can be prevented and detected. This chapter describes a range of disorders of potato tubers, categorizing them as external, superficial or internal. In each case, a description of symptoms is given, followed by information about the causes of the disorder and ways of preventing and minimizing its symptoms.