Two types of furnaces (a mid-size furnace denoted as Furnace 1 and a small-size one denoted as Furnace 2) commonly used for burning joss paper, located in two temples in southern Taiwan, were selected for this study. With similar burning devices (semi-open systems), both furnaces can be used to burn joss paper with the aid of natural air supply through the inlets of furnace. In order to characterize peak emission of PCDD/Fs (usually on festival days) in the selected temples, the sampling campaigns were conducted during the festival period in September 2008. It was found that the mean total I-TEQ contents in the original (unburned) joss paper from Furnaces 1 and 2 were 1.41 and 4.51 ng I-TEQ/kg, respectively. The mean total I-TEQ content in the residue of burned joss paper from Furnace 1 (7.97 ng I-TEQ/kg) was approximately 15-fold that of Furnace 2 (0.490 ng I-TEQ/kg). OCDD was the most abundant congener in the joss paper and in the residues from burned joss paper. Moreover, the emission factor of total PCDD/Fs I-TEQ content of Furnace 1 (0.176 ng I-TEQ/g-feedstock) was one to two orders of magnitude higher than that of Furnace 2 (0.0203 I-TEQ/g-feedstock). This phenomenon is probably associated with the high chlorine content in the unburned joss paper of Furnace 1, and high exhaust temperature from burning joss paper in Furnace 1 (271oC) was possibly within a range that might highly promote de novo formation of PCDD/Fs. It is necessary for the investigated furnaces to install air pollution control devices in order to reduce the PCDD/F emission from joss paper burning.