BACKGROUND Porphyria Cutanea Tarda (PCT) is the most common form of porphyria. It is characterised by lowered activity of uroporphyrinogen decarboxylase. It seems possible that the hepatitis C virus (HCV) infection triggers the symptoms of PCT. MATERIAL AND METHODS A group of 29 PCT patients (33-73 years old, mean 54 years) was evaluated. In these patients the serum HCV-RNA (by mean of automatic Cobas AmplicorTM Hepatitis C ver. 2.0 assay, Roche Diagnostics), activity of transaminases (ALT, AST), serum protein fractions, iron, total iron binding capacity (TIBC), ferritin, transferrin, transferrin saturation, and urinary porphyrins excretion were assessed. RESULTS The presence of HCV-RNA was detected in 12 cases (41.4%). Statistically important differences between currently HCV infected patients and other PCT patients concerned the following parameters: mean body mass (68.5 vs. 78.0 kg, p = 0.02), mean body mass index (22.4 vs. 26.8 kg/m2, p = 0.007), mean serum activities of ALT (112.6 vs. 65.4 U/l, p = 0.02) and AST (85.0 vs. 56.5 U/l, p = 0.038), total serum protein concentration (78.0 vs. 71.6 g/l, p = 0.016) and serum alpha-2 protein concentration (7.2 vs. 5.5 g/l, p = 0.009), respectively. Some other not significant differences were also found: mean serum iron level 182 vs. 169 micrograms/dl, transferrin concentration 2.77 vs. 2.56 g/l, transferrin saturation 43 vs. 45%, serum TIBC 445 vs. 397 mg/dl and ferritin concentration 394 vs. 400 micrograms/l, respectively. The mean urinary uroporphyrin concentrations were 643 micrograms/l vs. 366 micrograms/l (p = 0.16) and those of coproporphyrins were 190 micrograms/l vs. 136 micrograms/l (p = 0.37), respectively. CONCLUSION In the group of PCT patients investigated no significant relationship between current HCV infection and iron or porphyrin metabolism was noted. Nevertheless, HCV infection significantly influences the symptoms of liver damage and seems to influence other metabolic parameters in PCT patients.