This study presents the first investigation of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/F) emission from (six 2-stroke and six 4-stroke engine) motorcycles using chassis dynamometer tests. Effects of engine type and lubricant renewal on PCDD/F emission were also evaluated. The mean total PCDD/F emission concentration of tested motorcycles was 1.06 ng/Nm3, with a corresponding mean total PCDD/F I-TEQ of 0.0671 ng I-TEQ/Nm3. The mean PCDD/F emission concentration of 2-stroke engine motorcycles (1.17 ng/Nm3, 0.0727 ng I-TEQ/Nm3) was more than that (0.912 ng/Nm3, 0.0534 ng I-TEQ/Nm3) of 4-stroke engine motorcycles. The PCDD/F emission factors of motorcycles were comparable to those of some types of vehicles, although the tested motorcycles equipped with cylinders much smaller than those of vehicles. The dominant PCDD/F congeners of 2-stroke and 4-stroke motorcycles in emission priority were OCDD, OCDF, 1,2,3,4,6,7,8-HpCDD, and 1,2,3,4,6,7,8-HpCDF, accounting for 37%, 15%, 10% and 9% of the total PCDD/F emission, respectively. The reductions of PCDD/F and I-TEQ emissions after lubricant renewal of the 4-stroke motorcycles were 26%–45% and 41%–63%, respectively.