Dried bloodstains on glass were exposed for up to 30 minutes to five different light sources: Argon ion laser, Polilight UV, Polilight green, Superlite, and shortwave UV. The bloodstains were subsequently analyzed using a quadruplex PCR system. The testing found that treating the bloodstains with four of the five light sources had no appreciable effect on the results obtained from subsequent PCR analysis; however, exposure of the bloodstains to shortwave UV light for more than 30 seconds precluded the acquisition of results from PCR testing. Therefore, under casework conditions, it would be preferable to avoid exposing bloodstains to shortwave UV when PCR typing is to be performed on the bloodstains. This is a preliminary study. A more intensive project to investigate the effects of increased exposure times and additional light sources on STR typing of a range of body fluids would complement the result obtained so far. The results from additional studies would relate more closely to operational casework scenarios if the effects of environmental contaminants in these experiments were also assessed. 1 table, 2 figures, and 13 references