Mercury is a known neurotoxin that is particularly harmful to children and unborn fetuses. Consumption of contaminated fish is one major route of mercury exposure. This laboratory experiment gives students an opportunity to measure mercury concentrations in store-bought seafood and compare the results to suggested exposure limits. The U.S. Environmental Protection Agency (EPA) recommended method for determination of mercury concentrations is cold-vapor atomic spectroscopy. We propose a method of adapting an existing flame atomic absorbance spectrometer for this technique with little additional cost, thus allowing students to learn about this important technique. Students measured mercury concentrations in swordfish and tuna purchased at a local supermarket. Mercury levels in both fish were within the range found by the U.S. Food and Drug Administration (FDA). Students gained experience with sample digestion, cold-vapor analysis, and data analysis. (Contains 1 table and 1 figure.)