A one year study (April 1998 to May 1999) was conducted on the Cacique reef flat in the Caribbean coast of Panama. Of 49 species of benthic macroalgae encountered, 17 (35%) were Chlorophyceae, 13 (26%) Phaeophyceae and 21 (43%) Rhodophyceae. Among the Chlorophyceae, Bryopsidales order comprise the largest number of species (14) and Udoteaceae was the most common family. 8 species of Phaeophyceae belonged to Dictyotales order and Dictyotaceae family and 5 species to the Fucales order, Sargassaceae family. 7 orders of Rhodophyceae were recorded, with the species belonging to Ceramiales, Rhodomelaceae family being dominant. Seasonality was evident on the Cacique reef flat. The number of benthic macrophytes species showed an increasing trend from windy season to the calm season.