Diabetes itself, by its nature, can aggravate the symptoms of depression. One of its main complications is peripheral diabetic neuropathy (PDN). Based on the literature the presence of the relationship between the PDN and depression is confirmed. The symptoms connected with instability while walking and reduction of everyday activities were the strongest predictors of the intensification of depression symptoms. The relationship between the neuropathic ulcers and depression is considered as ambiguous. Additional problems in diagnosis and evaluation is the polyetiologic character of the disease, damage to the nerve fibers of different thickness, variety of methods of the diagnosis and differences in the prevalence of diabetic neuropathy (26%–50%). The presence of the described differences may be connected with diagnostic methods and the fact of the modification of perceived symptoms such as pain by the depression itself. One of the results of difficulties in describing the relationships and diagnosis are problems, described in the literature, with the selection of patients requiring treatment of PDN.