Activity of rheumatoid arthritis (RA) has been evaluated by various biomarkers including matrix metalloproteinase (MMP)-3, but the relationship between the levels of biomarkers and elevation of pulmonary artery systolic pressure (PAs) has not been evaluated in detail. We sought to determine the utility of MMP-3 with other biomarkers for the prediction of PAs in patients with RA. Blood samples for biomarkers and echocardiography were obtained in 100 consecutive patients with RA. PAs was measured by continuous-wave Doppler echocardiography and was correlated with laboratory findings. PAs had a fair correlation with MMP-3 (r = 0.53, p < 0.001) and a weak correlation with KL (Krebs von den Lungen)-6 (r = 0.36, p < 0.001) and rheumatoid factor (r = 0.25, p = 0.011). MMP-3 had a fair correlation with pulmonary vascular resistance (r = 0.42, p < 0.001), but MMP-3 was not related to cardiac output (r = 0.09, p = 0.352). Thirty-nine patients had impaired left ventricular diastolic function. There was no significant differences in PAs and pulmonary vascular resistance (PVR) between the patients with and without impaired left ventricular diastolic function. When 5 variables (age, MMP-3, C-reactive protein, KL-6, and rheumatoid factor) were used in the multivariate analysis, MMP-3 (partial regression coefficient = 0.553, p < 0.001) emerged as the most important variable related to the elevation of PAs. Nine patients (9%) were diagnosed to have pulmonary hypertension by echocardiography. MMP-3 value of 245 ng/ml was the optimal cut-off value for the prediction of pulmonary hypertension (sensitivity: 100%, specificity: 67%, area under the curve 0.89). Thus, a close relation of MMP-3 with PAs and PVR indicate that rise in PAs in patients with RA was ascribed to increase in PVR due to underlying systemic inflammation-mediated pulmonary vascular remodeling.