This chapter provides some updated information on contemporary methods for hormone and β-agonist analyses. It deals with the classical approaches for the effective detection and identification of exogenous hormones. The chapter examines specific problems related to control strategies for natural hormones. These include both the traditional and generally recognized natural hormones as well as a series of androgenic steroids that can be present in biological samples obtained from a series of species. The fact that natural background concentrations can be present strongly complicates the analyses. The application of mass spectrometry (MS) in combination with gas chromatography (GC) or liquid chromatography (LC) is considered the "gold standard" for analytical methods in residue analysis. The chapter presents an overview of the available bio-based screening methods for the detection of hormones and ß-agonists, focusing on estrogens, androgens, progestogens, corticosteroids, thyroids, ß2-agonists, and growth hormones (GH).