The objective of this study was to analyse the association between serum homocysteine (Hcy) levels and the presence of Raynaud's phenomenon (RP) in a cohort of systemic lupus erythematosus (SLE) patients. We enrolled premenopausal, disease-inactive SLE patients ( n = 34) with RP (group I, n = 11) or without RP (group II, n = 23), and age-matched healthy premenopausal women as controls (group III, n = 20). Fasting Hcy levels were determined for all these subjects. The results reveal that group I patients exhibited significantly greater serum Hcy levels (11.68+/-2.98 mmol/l) than group II patients (8.29+/-2.89 mmol/l) ( P = 0.003), and group III healthy subjects (8.00+/-1.50 mmol/l) ( P = 0.001); however, in this regard there was no significant difference between group II and group III patients ( P = 0.927). In conclusion, elevated serum Hcy levels were noted for this cohort of SLE patients with RP compared to those not evidencing RP and healthy controls. Although the pathogenesis of RP still remains obscure, this study suggests that Hcy may play a role in the aetiopathogenesis of SLE patients with RP.