The LAPD19 Symposium is the continuation of a biennial series that began at Kyushu University in 1983. It brings together physicists and chemists in diverse areas of laser-based plasma diagnostics including the physics of nuclear fusion, laser physics and low-temperature plasma chemistry and physics. The symposium aims to promote cross-pollination of these fields via fruitful discussion, and covers all diagnostics using electromagnetic waves (lasers and microwaves) applied to fusion plasmas, industrial process plasmas, environmental plasmas, plasmas for medical applications, atmospheric plasmas, plasmas in liquids and other plasma applications. Topics on hardware developments related to laser-aided plasma diagnostics are also welcome. Instrumentation developments related to laser-aided plasma diagnostics also received emphasis in the program.