PUVA is a well-established and effective treatment for plaque stage mycosis fungoides (MF) but its use is limited on a long-term basis because of the risk of cutaneous carcinogenesis. A further disadvantage is that nonexposed areas (sanctuary sites) often develop persistent disease. Therefore it is important to find alternative methods of treatment. Extracorporeal photopheresis (ECP) is a form of photochemotherapy that involves exposure of white blood cells to UVA with psoralens and can be effective in Sézary syndrome and erythrodermic cutaneous T-cell lymphoma. The aim of this study was to compare the efficacy of PUVA and ECP in the treatment of patients with T2 plaque stage (Stage 1B) MF who had a detectable peripheral blood T-cell clone. The study was of a cross-over design. Sixteen patients were randomized to receive either PUVA twice weekly for 3 months followed by ECP once monthly for 6 months at relapse, or vice-versa. Response was assessed by monthly skin scores and peripheral blood T-cell clonality. Ten patients received PUVA initially and six ECP initially. Eight patients completed the study. Skin scores taken at the completion of each treatment arm in patients who completed the study were 113 units better (confidence interval, 42–184 units) following 3 months PUVA than 6 months ECP (P = 0.002). Peripheral blood T-cell clones were detectable in all patients post-treatment. This study indicates that ECP is not effective in the treatment of plaque stage (1B/T2) MF even in patients with molecular evidence of a peripheral blood T-cell clone. Although PUVA was more effective than ECP, neither treatment modality cleared malignant T-cells from the peripheral blood.