Room temperature phosphorescence (RTP) signals on filter paper depend on experimental conditions including type of filter paper, drying and cooling times of the paper after spotting the sample, and type and concentration of heavy-atom present. RTP of biphenyl, as a model compound, on six filter papers using eleven different heavy-atoms is examined. The highest RTP signal is observed when S&S 903 filter paper is used and dried in an oven at 110°C for 10 min and cooled in a nitrogen gas stream for 10 min. RTP characteristics of several polychlorinated congeners and mixtures are presented without and with the presence of different heavy-atoms; RTP intensities increase and the limits of detection decrease. Lifetimes of all compounds exhibiting RTP are measured. An RTP comparison study of several PCBs on two different types of filter papers is also reported.