Ultraviolet (UV) curing with light emitting diodes (LED) has gained significant popularity in the past 8-10 years. In comparison to UV curing with medium pressure lamps, the UV-LEDs show advantages and disadvantages when curing lithographic inks. The spectral distribution of the UV sources coupled with the absorption spectra of the photoinitiators used provides insight into the film properties of the cured inks. Both technologies allow for commercial, publication and packaging applications which are gaining some market share versus conventional lithographic printing inks. Curing parameters and print quality will be discussed with respect to lithographic printing inks in both web offset and sheetfed applications.