The endemic catfish of the Magdalena River Basin Pseudoplatystoma magdaleniatum (Siluriformes: Pimelodidae) constitutes the second species in commercial importance and a target species for fishing management. To contribute to supports decision making on regulatory measures, it was evaluated their reproductive strategies in five points of influence on the basin: three in the Magdalena River, one in the Cauca River and one in the San Jorge River. Sampling was conducted since April 2012 to March 2013. Mature females (stages III and IV) were sampled (total and eviscerated weight) and gonads were removed and weighed. The ovarian samples were analyzed macroscopically and microscopically. By using the Image J and Image Tool Program it was determined the average diameter of mature oocytes in second phase 0.7 mm. The effective fecundity fluctuates between 900 000 and 1062 000 and the oocytes corresponds to a semelparous type.