Protein phosphorylation is a reversible post-translational modification (PTM) influencing protein localization, protein-protein interactions, and intracellular protein activities. This PTM is the key chemical signal in complex molecular networks and pathways, which controls gene expression and in turn cell behavior in response to extracellular signals. Dysfunctions in the signalling network commonly involves enhanced kinase activity and abnormal phosphorylation is thus a common hall mark of several diseases with cancer as a notable example. In spite of genetic alterations being the underlying cause for these defects, the direct identification and quantification of distinct protein phosphorylation events is needed to understand the disease driving mechanisms and in turn to tailor therapies at an individual level. This has spurred the development of functional phosphoproteomics, most frequently based on affinity-based phosphopeptide enrichment combined with advanced mass spectrometry (MS). This technique is capable of detection, sequencing and quantification of thousands of protein phosphorylation sites in large-scale experiments. In spite of the scalability, speed and sensitivity of current phosphoproteomics methods, robustness is typically insufficient for its routine use for instance in clinical settings. This may be addressed by targeted phosphoproteomics involving site-specific phosphopeptide enrichment and selective MS readout techniques. This in turn paves the way for routine multiplex biomarker quantifications, a requirement for the technique to be useful for routine use. Immunobased phosphopeptide enrichments have in this context emerged as one enabling tool allowing deep profiling of multiple phosphopeptides in a reproducible and robust assay format. This is offset by current limitations in delivering antibodies fulfilling high specificity, high affinity as well as high reproducibility and the highly variable immunogenicity of phosphopeptides per se. To compensate for this lack of affinity tools, we set out to investigate whether molecular imprinting technology could fill this gap.