Pulsed UV light (PUV) was investigated as a means to rapidly increase vitamin D(2) (D(2)) content in fresh button mushrooms (Agaricus bisporus). D(2) was found to increase to over 100% RDA/serving following 3 pulses (1 s). Following 12 pulses, D(2) began to approach a maximum concentration of 27 μg/g DW. The D(2) produced with 3 pulses decreased from 11.9 to 9.05 μg/g DW after 3 days of storage; however, D(2) levels remained nearly constant after this point throughout an 11-day shelf life study. PUV treated sliced mushrooms produced significantly more D(2) than whole mushrooms, and it was also observed that brown buttons generated significantly less D(2) than white buttons. Several quality attributes were assessed, and no significant differences between control and PUV treated mushrooms were observed. These findings suggest that PUV treatment is a viable method for rapidly increasing the D(2) content of fresh mushrooms without adversely affecting quality parameters.