Molecular recognition is an emerging field of Supramolecular Chemistry. The major challenge for supramolecular chemists is detection in an aqueous medium. However, most biological and environmental processes happen in an aqueous medium; therefore, chemosensors that can operate in water are highly demanded. This review mainly focuses on the recognition of analytes (metal, anion and biomolecules) in an aqueous medium (≥90% water) and demonstrates that sensing in an aqueous medium can be achieved without compromising the selectivity and sensitivity. The detail discussion on the design of chemosensors and the mechanism of action for detection of metal ions, anions and biomolecules in an aqueous medium has been provided, reported in the period of 2001–2015.