The occurrence of toxic red tide outbreaks is an environmental and public health hazard in the Philippines. Thus, it is necessary to develop 'monitoring programs to protect the shellfish industry and the general public. Previous methods for the detection of paralytic shellfish poisoning (PSP) toxins make use of mouse bioassays and/or fluorescence detection through High Performance Liquid Chromatography (HPLC). The mouse bioassay, while cheap and rapid, requires a large amount of sample, and is capable of detection of toxin concentrations that are already near the regulatory limit. Fluorescence HPLC analysis of derivatized PSP samples is destructive and is not sufficiently reproducible. We report a new procedure for the rapid detection of components of samples contaminated by Pyrodinium bahamense var compressum using a combination of reverse-phase HPLC and electrospray mass spectrometry. The procedure is fast and requires minimal amounts of sample, so that purified toxins need not be derivatizated as a prerequisite for its detection. In addition, results from this study complement earlier findings that the main toxic components of Philippine toxic red tide are neosaxitoxin, decarbamoylsaxitoxin, and gonyautoxin.