Blooms of the Florida red tide dinoflagellate Gymnodinium breve occur in oligotrophic west Florida shelf waters which are depauperate of both dissolved inorganic nitrogen (N) and phosphorus (P). The nutrient stoichiometry of a small (maximum G. breve concentration 1.1 x 106 cells l^-1), nearshore bloom which persisted off Sanibel Florida from November 1998 to February 1999 was examined using particulate nutrient measurements from both the Florida shelf area and the bloom itself. The bloom was characterized by unique C/Chl, C/N and N/P ratios which differed from surrounding (ie. nearshore without G. breve present, offshore (~100 km) surface waters or the deep chlorophyll maximum (DCM)) areas. Chlorophyll a was only slightly elevated in the bloom (3.6 mg l-1) compared with both offshore and nearshore waters (0.16 mg l-1 to 1.87 mg l-1), however C/Chl ratios of the bloom ranged from 84.6 to 296.1 while those of nearshore, offshore and DCM areas ranged from 104.5-692.0, 355.9-2529.5 and 84.6-421.6 respectively. The variability and large range of C/Chl values may be due to variability in detrital contribution to carbon or extremely low chlorophyll concentrations. Both low inorganic N and P concentrations and stoichiometric calculations of N and P requirements based on observed bloom biomass suggest that sufficient P and insufficient N was present to support the bloom. However, N/P ratios for both bloom (15.9-46.6) and non-bloom (21.9-57.36) areas were consistently greater than Redfield thoughout this period, suggesting an unidentified N source was available to both bloom and shelf phytoplankton populations on the west Florida shelf.