Porphyria cutanea tarda has rare clinical presentations and in some cases is characterized by an atypical course of the disease, which leads to diagnostic errors. Objective. To analyze the reasons for delayed diagnosis of porphyria cutanea tarda in the Krasnodar region in 2011-2013. Material and methods. Medical history, complex of clinical symptoms, laboratory assays (iron and transaminase levels in blood serum, levels in uroporphyrin in urine and coproporphyrin in feces) were analyzed for patients with porphyria cutanea tarda. Results. The examination revealed insufficient completeness of the collected medical history, associated comorbidities and clinical and laboratory studies. Deferred biochemical studies revealed high transaminase level in serum, iron levels, uroporphyrins in urine and coproporphyrins in feces. Conclusion. Stage-by-stage adherence to the diagnostic algorithm, which covers medical history, specific features of clinical presentation, results of comprehensive diagnostic examination, including biochemical studies of indicators of impaired metabolism of porphyrins, allows one to timely diagnose porphyria cutanea tarda, to determine the proper approaches to treatment and to achieve stable remission.