The present ability of atomic and molecular fluorescence techniques to monitor quantitatively the concentrations of species in flames is reviewed. Atomic fluorescence measurements require a saturation mode with a laser pulselength that is sufficiently short to avoid induced chemical or ionization effects but long enough to produce a steady state distribution over the accessible energy levels. Molecular fluorescence techniques are available for both low laser power and saturated modes of operation and invariably involve some level of approximation due to the complex energy level manifold that is involved. Two-photon induced fluorescence detection of atoms and molecules is of potential interest in facilitating the monitoring of various additional species that previously was only possible spectroscopically in the vacuum ultraviolet. Results of the major applications of these techniques are presented. These include temperature measurements, studies of the SOX and NOx flame chemistries, methods of obtaining energy transfer rates, laser induced chemical kinetic data, and their potential for deriving thermochemical values.