Background:Systemic sclerosis (SSc)–associated interstitial lung disease (ILD) (SSc-ILD) is a serious systemic SSc manifestation that has a high morbidity and mortality rate. That necessarily requires using of appropriate, accurate, and sensitive assessment tools. Objectives:Lung ultrasound B-lines and serum Krebs von den Lungen-6 (KL-6) are identified as newtools for diagnosis ILD. The aim of our work was to assess the role of B-lines and serum KL-6 as indicators of the severity of SSc-ILD. For this objective, the correlation among B-lines score, serum KL-6 levels, high-resolution computed tomography (HRCT) score, and pulmonary function tests were investigated in SScpatients. Methods:36SSc patients underwent chest HRCT scans, lung ultrasound and pulmonary function tests examination. The Warrick score was used to estimate severity and extent of ILD at HRCT. The B-lines score indicating the extension of ILD was calculated by summing the number of B-lines on a total of 14 scanning sites. Serum KL-6 levels (U/ml) was measured byenzyme-linked immunosorbent assay (ELISA). Results: A positive correlation was found between the B-lines score and serum KL-6 levels (r 0.9, P <<0.001), and between the Warrick score and serum KL-6 levels (r 0.909, P < 0.001). Also positive correlation between B-lines score and the Warrick score (r 0.885, P <<0.001) was confirmed. Both B-lines score and KL-6 levels inversely correlated to with forced vital capacity (r -0.582, P < 0.001and r-0.79, P < 0.001, respectively), forced expiratory volume in 1 s (r -0.482, P < 0.015 and r -0.661, P < 0.001, respectively) and diffusion capacity for carbon monoxide (r -0.461, P < 0.041) and r -0.582, P < 0.001, respectively). Conclusion: B-lines score and serum KL-6 levels correlate with HRCT findings and PFTs, indicating that they can be used to assessment the severity of SSc-ILD.