Little data have been available concerning chain breaking or an increase in the degree of oxidation of cellulose during exposure to the visible and near-ultraviolet radiation emitted by ordinary daylight fluorescent lamps under moderate conditions of temperature and humidity, both during exposure and during subsequent thermal degradation. The present investigation, involving papers of little or no lignin content, and unbleached and bleached kraft pulp as well as filter paper, revealed moderate immediate effects of exposure as well as sensitization towards subsequent thermal degradation. Intervention of an ultraviolet filter noticeably reduced, but did not prevent, deterioration both during exposure and during subsequent aging of 50% relative humidity (RH) and 90°C. Continuous exposures of 800,000 to 1,300,000 footcandle hours were involved.