This study aimed to investigate the effect of four different light-emitting diode (LED) wavelengths on calcification and proliferation of osteoblast-like cells in vitro. MC3T3-E1 cells were seeded within three-dimensional collagen scaffolds and irradiated daily by LED light with peak emission wavelengths of 630-, 680-, 760- and 830-nm at constant fluency of 3.1 J/cm 2 (irradiance intensity 2 mW/cm 2 ). Cultures were measured for calcium content at day 0, 7, 14, 21, 28, 35 and 42. The significant enhancement in calcium content was observed at the early stage of culture (days 7 and 14) (p