Measurement and application of compound properties for candidate selection and optimization is an emerging trend. Property-based design supplements successful activity-based strategies to produce drug-like candidates. High-throughput screening hits are evaluated for integrity and aggregation to ensure quality leads. Solubility data assures accurate activity assays and predicts absorbance. Cellular and artificial membrane permeability assays indicate compound penetration through membranes in cells, intestine and blood-brain barrier. Lipophilicity and pK(a) provide fundamental structure design elements. Stability in liver, plasma and buffer evaluates compound lifetime. Drug-drug interaction is predicted using CYP inhibition assays. Drug-like properties are vital to successful drug candidates and enhance drug discovery.