Currently, liquid chromatograph–ultraviolet spectrometry (LC–UV) is typically applied to cleaning validations because of its familiarity, robustness, ease of use, and regulatory acceptability. For low-dose compounds, equipment requiring low residue limits, and compounds lacking strong chromophores, the enhanced sensitivity and selectivity of liquid chromatography–mass spectrometry–mass spectrometry (LC–MS–MS) facilitates rapid method development for the detection of low levels of residues of active pharmaceutical ingredients (APIs). LC–MS–MS is an acceptable technique for the analysis of API residues for cleaning validation. More importantly, in applications where sensitivity and selectivity are inadequate using traditional modes of detection, LC–MS–MS offers substantial advantages. LC–MS–MS will afford faster development and analysis time, potentially making it the predominant tool of choice.