Objectives: Pulmonary hypertension and right ventricular (RV) dysfunction are severe complications of systemic lupus erythematosus (SLE). The role of increased pulmonary artery stiffness (PAS) has not been studied in RV dysfunction. We investigated the relationship between PAS and RV function in SLE patients without cardiovascular symptoms. Study design: The study included 32 patients with SLE (30 males, 2 females; mean age 34±9 years) and 30 age- and sex-matched healthy controls (28 males, 2 females; mean age 36±5 years). All the subjects underwent echocardiographic examination. Using Doppler echocardiography, PAS was calculated by dividing maximal frequency shift of the pulmonary flow by the acceleration time. To assess RV function, RV myocardial performance index (MPI) was determined by the sum of isovolumetric contraction and relaxation times divided by the ejection time. In addition, tricuspid annular plane systolic excursion (TAPSE) was measured on two-dimensional M-mode recordings. Results: Compared to the control group, patients with SLE exhibited significantly higher PAS (p=0.004) and RV MPI (p=0.001), and lower TAPSE (p=0.001). In univariate correlation analysis, SV MPI was significantly correlated with PAS (r=0.60, p=0.001), age (r=0.48, p=0.003), SLE duration (r=0.51, p=0.002), and pulmonary artery systolic pressure (r=0.36, p=0.03). Multivariate linear regression analysis showed that PAS (95% Cl 0.002-0.005; p=0.001) and SLE duration (95% Cl 0.001-0.004; p=0.004) were independently associated with RV MPI. In addition, a significant inverse relationship was found between TAPSE and RV MPI (r=-0.48, p=0.005). Twenty-four SLE patients had normal RV function (TAPSE 2:17 mm). Eight patients with RV dysfunction (TAPSE <17 mm) had significantly different RV MPI (p=0.001), PAS (p=0.002), age (p=0.04), and SLE duration (p=0.004). Conclusion: Our data suggest that increased PAS is strongly associated with the development of RV dysfunction in patients with SLE.