The objective of this study was to determine the composition and abundance of macroalgae belonging to the Chlorophyceae class associated with the rocky coast, in the Ojo de Agua area of Cabo de La Vela, department of La Guajira, Colombia, in order to know and expand the information about this resource in the Colombian Caribbean. The methodology consisted of taking eight samples of macroalgae along a 5 m transect in three sampling stations, by means of quadrants of 25 x 25 cm. In the laboratory, macroalgae were identified to the lowest possible taxonomic level and their dry weight was determined as a measure of abundance (biomass). A total of 4 species of macroalgae Chlorophyceae were found, specifically Caulerpa racemosa, C. sertulariodes, Ulva fasciata and U. lactuca. The highest average biomass obtained corresponded to U. fasciata (109 g / m2), with the highest average values in the middle zone of transect (107.2 g / m2). The class Chlorophiceae with a richness of 4 species at the time of the study, is represented mainly by the genus Ulva in the area Ojo de Agua, Cabo de La Vela, and is an important ecological component, for its greater abundance and at the same time a potential resource for biotechnological use.