In this book, we explore the potential applications of functionalized folic acid-polymer nanoparticles in gene and drug delivery. Folic acid-chitosan (carbohydrates) and folic acid-PAMAM (dendrimers) of different sizes were used to transport DNA, RNA and drugs in vitro. Thermodynamic analysis showed conjugation of DNA, RNA and drug to nanoparticles occurred via hydrophilic, hydrophobic, H-bonding and van der Waals contacts. Major alterations of DNA and RNA morphology occurred by nanocarrier interaction, while drugs induced polymer morphological changes. Functionalized folic acid-nanoparticles can deliver DNA, RNA and drugs to the target molecules.