A study investigated the diagnostic accuracy of lung ultrasound (LUS) versus high-resolution chest computed tomography (HRCT) in interstitial lung disease (ILD) in patients with rheumatoid arthritis (RA). Interstitial lung disease affects up to 60% of patients with RA, and HRCT is the gold standard, but involves radiation. Seventy-three patients (18 men, 55 women) with a mean age of 55 ± 12 years and a mean DAS28-ESR disease activity score of 3.47 ± 1.40 were included in the prospective cross-sectional study. HRCT identified ILD in 28.8% of patients, while LUS by semiquantitative score detected involvement in 21.9% of patients. The sensitivity of LUS was 59.1% and the specificity was 94.1%, with ROC analysis showing an area under the curve (AUC) of 0.813. The optimal cutoff of 5 B-lines gave a sensitivity of 63.6% and a specificity of 94.1%. The findings suggest that LUS may serve as a screening tool to identify patients in need of further HRCT.