The study examined 64 patients with idiopathic pulmonary fibrosis (IPF) or other progressive pulmonary fibrosis (PPF) who were treated with antifibrotic drugs from June 23, 2017, to June 23, 2022. The mean Clinical Frailty Scale (CFS) score was 5.02 ± 1.62, with 37 patients (58%) being frail (CFS ≥ 5) and 27 (42%) non-frail (CFS < 5). Frail patients were older (74.4 ± 4.66 years vs. 70.6 ± 4.78 years, p=0.004), had lower forced vital capacity (FVC 2.31 ± 0.75 L vs. 2.78 ± 0.75 L, p=0.004), lower diffusion capacity (DLco 35.52% vs. 54.6 ± 11.48%, p=0.003) and shorter 6-minute walking distance (305 ± 159 m vs. 410 ± 94 m, p=0.006). They also had a higher ILD-GAP index (4.62 ± 1.41 vs. 3.88 ± 1.18, p=0.037). Pulmonary function decline was not significantly different between groups, but frail patients more often required medication dose reduction due to adverse effects (51.3% vs. 26%, p=0.04). Frailty is associated with worse lung function and physical performance in these patients.