This book highlights the fabrication of various types of solid, hollow, and dissolvable microneedles (MNs) using various synthesis processes and their applications in medicine, agriculture, and sensors. MN-based technology emerges as a sign of hope, offering a painless delivery system. In general, MN-based technology uses tiny needles to puncture the outermost layer of the skin. MNs are made of various materials like metals, silicon, and polymers for efficient delivery of biomolecules. With the tremendous success of MNs in the drug delivery system, researchers try to use MNs in agriculture and sensor applications to improve plant health via monitoring and delivery of agrochemicals. By modulating the materials of MNs, drugs and biomolecules can be delivered in a controlled manner. In general, MN-based technology holds significant opportunities for improving delivery of the drugs/biomolecules and opens new wings toward agriculture and sensing applications. Moreover, MN-based technology enables newer avenues for therapeutic and diagnosis of diseases.