Caranx hippos is one of the most important fish resources in Colombia, particularly in artisanal fisheries. In order to deepen C. hippos biological knowledge, fecundity (number of eggs in development) and oocyte diameter was estimated. Fish samples were collected from commercial artisanal fishing trips, each fish was measured (total length, Lt) and weighted (total weight, Pt); gonads were removed, weighed and analyzed for determining fecundity using a gravimetric method combined with image analysis performed using the open access software Image J®. From the measurement of 149552 oocytes, an average diameter of 0.32 ± 1.24E-4 mm, was obtained, while fecundity varied between 291439 and 4380480 oocytes per gonad. No direct relationship was evidenced between egg number and diameter, and fish size and weight. Mature oocyte microstructural development is described, average diameters in cortical alveoli and vitellogenesis were 98.6 + 33.1 μm y 207.5+ 59.6 μm, respectively. This result suggests that larger females are not always the more fertile. Given the importance of C. hippos in Colombia, this work is a valuable contribution to the knowledge of the species, which can be used in fishery models with direct applicability to management procedures.