The development and application of chemical methods for monitoring paralytic shellfish poisoning (PSP) in coastal waters requires the availability of pure PSP standards. However only a few toxins are commercially available and only very small amounts of some of the other 18 PSP toxins identified are available at some research laboratories. A project is currently in progress for the isolation and purification of significant quantities of PSP toxins from contaminated mussels under the auspices of the Community Bureau of Reference of the Commission of the European Communities (BCR Programme). The PSP toxins from hepatopancreas of 500 kg of whole mussel were extracted and purified, and the following toxin profile was determined using a method based on Oshima et al. [1] GTX1, (24%), GTX2 (<1%), GTX3 (<1%), GTX4 (2.4%), GTX5 (5.8%), GTX6 (35.4%), C1 (11.5%), C2 (1.22%), neo-STX (11.4%), dc-STX (6.2%) and STX (2.4%). These toxins can be separated into three different fractions (STX-group, GTX-group and C-group), before proceeding to the purification of the individual toxins.