Background. Ischaemia-modified albumin (IMA) is increased in diseases associated with oxidative stress, as detected using the albumin cobalt-binding test. Oxidative stress plays an important role in the development of psoriasis. Aim. To investigate circulating IMA levels in patients with psoriasis and its association with the disease characteristics. Methods. Serum IMA and albumin concentrations were evaluated in 26 patients with psoriasis and 26 healthy controls matched for age, gender and body mass index. Levels of albumin, IMA and adjusted IMA were compared between the groups. Results. IMA and adjusted IMA were significantly higher in patients with psoriasis [0.55 +/- 0.04 and 0.54 +/- 0.05 absorbance units (ABSU), respectively] than in healthy controls (0.38 +/- 0.04 and 0.38 +/- 0.05 ABSU, respectively). The two groups had similar albumin levels, but there was a negative correlation between IMA and albumin levels in patients with psoriasis. IMA did not correlate with any disease characteristics. Conclusions. IMA levels are higher in patients with psoriasis than in healthy controls. IMA might be produced through an adaptive response to chronic hypoxia and oxidative stress, which might play a role in the systemic inflammation seen in psoriasis.