This book chapter offered an overview of the several types of peptide-based nanomaterials as (bio)sensors. It highlighted the recent advancements in related technologies during recent years. Peptide-based nanomaterials can be applied to several analytical techniques including electrochemical methods, electrochemiluminescence, and optical methods (UV-Vis-NIR spectroscopy, colorimetric, fluorescence, Raman spectroscopy, and surface plasmon resonance). They offered the quantification of target analytes in the sub-nanomolar range. They can be integrated into advanced nanotechnology. Peptides are effective nanomaterials for the development of sensitive and convenient biosensors. Peptide-based biosensors were applied for the detection of analytes, e.g., biomarkers, metal ions, pollutants, explosive materials, and antibodies. Precise chemical engineering of a peptide can serve as an alternative to an antibody offering significant advantages including enhanced tolerance to environmental conditions, and customizable sequences for detecting a diverse array of targets. Peptide-based nanomaterials can be used for large-scale sensor manufacturing. Peptide-based biosensors advanced clinical diagnosis.