Nopal is an originary plant from Mexico, it can growth under extreme conditions, it is also an ancestral crop that help to establish the mexican civilization. Nopal and its products, including fruits are considered a key crop for food sufficiency and security in Mexico. Prickly pear (cactus fruit) shows great variability in its morphology, however there are two disadvantages: the number and size of seeds and thorns; it will be interesting to identify the molecular processes associated to these characteristics. the main objective of this work is to identify the molecular mechanisms that regulate the development of prickly pear. Tissues from four stages were collected; flowers, fertilized button, green and ripe fruit from an intermediate ripening morphospecie (Reina). miRNA expresión at this stages was analyzed with a microarray and a transcriptome expression, computational analysis helped to identify and select unique miRNAs from each developmental stage. A total of 43 miRNAs with 26 different targets were identified in relation to fruit development from flower induction. It highlights the importance of miR172 and miR395, as key candidates in the fruit ripening time. miR397 is also established, as an opportunity for the generation of varieties for control of seed production. The mechanism of action of microRNAs was tested in other plants successfully.