Abstract Polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs) were measured by the same laboratory at the same time period in four serial fat biopsy samples taken over a 3.5 year period from a single patient exposed to soot contaminated with PCDD/Fs. PCDDs/PCDFs were also determined in a single blood sample taken at the time of the last biopsy and compared to adipose tissue levels on a lipid basis. Most of the PCDDs/Fs were stable over the sampling period. However, 2,3,4,7,8-PnCDF, 1,2,3,4,7,8-HxCDF, and 1,2,3,4,6,7,8-HpCDF were somewhat elevated at the earlier time periods compared to current North American levels and decreased over time suggestive of half-lives for elimination of, at most, approximately 1 to 2 years. The PCDDs/PCDFs, except for OCDD, in a paired sample of whole blood and adipose tissue when expressed on a lipid basis were within 50% of each other for all the 2,3,7,8-substituted analytes.