Extracorporeal photochemotherapy (EXP) is an immunomodulating therapy that has been used in a limited number of patients with systemic sclerosis (SSC) with controversial results. The present study was performed to evaluate the efficacy and safety of extended EXP with extracorporeal application of liquid 8‐methoxypsoralen (8‐MOP) in the treatment of SSC. Eleven women with progressive SSC of recent onset were treated for a period of 16–57 months. Skin changes, physical performance, extracutaneous manifestations, and quality of life were evaluated before initiation of EXP and at regular intervals thereafter. From the start to the last set of EXP, we observed an overall improvement and/or stabilization of skin changes and physical performance in 5 of 11 patients (45%). Extracutaneous manifestations deteriorated in 10 of 11 patients (91%) (P<0.05), and quality of life deteriorated in 9 of 11 patients (82%) from a mean score of 10 before, to 17 at the last set of EXP (P<0.05). No major side effects were noted. Extended EXP with extracorporeal administration of 8‐MOP is a safe and well tolerated treatment modality. However, it provides only (minor) improvement of skin changes of a subset of SSC patients and does not beneficially influence extracutaneous manifestations and quality of life.