The most common preclinical, in vivo model to study lung fibrosis is the bleomycin-induced lung fibrosis model in 2-3-month-old mice. Although this model resembles key aspects of idiopathic pulmonary fibrosis (IPF), there are limitations in its predictability for the human disease. One of the main differences is the juvenile age of animals that are commonly used in experiments, resembling humans of around 20 years. Because IPF patients are usually older than 60 years, aging appears to play an important role in the pathogenesis of lung fibrosis. Therefore, we compared young (3 months) and old mice (21 months) 21 days after intratracheal bleomycin instillation. Analyzing lung transcriptomics (mRNAs & miRNAs) and proteomics, we found most pathways to be similarly regulated in young and old mice. However, old mice show an imbalanced protein homeostasis as well as an increased inflammatory state in the fibrotic phase compared to young mice. Comparisons with published human transcriptomic data sets (GSE47460, GSE32537 and GSE24206) revealed that the gene signature of old animals correlates significantly better with IPF patients and it also turned human healthy individuals better into "IPF patients" using an approach based on predictive disease modelling. Both young and old animals show similar molecular hallmarks of IPF in the bleomycin-induced lung fibrosis model. Although, old mice more closely resemble several features associated with IPF in comparison to young animals.