Agave colimana, subgenus Littaea (Asparagaceae) is a wild plant that belongs to the Asparagaceae family, and in this species, the formation of its female reproductive system is unknown, probably because it has no commercial use. However, A. colimana recently has been considered as a candidate for marketing as a succulent plant because of its floral and growth architecture. Knowledge about aspects of the formation of the embryo sac is useful for understanding its sexual reproduction, which is important for propagation by seed and breeding purposes. Megasporogenesis and megagametogenesis were studied using Feulgen staining under confocal microscopy. Megasporogenesis resulted in the formation of a linear tetrad with the functional megaspore attached to the chalazal end. Subsequently, megagametogenesis from the functional megaspore was followed by three mitotic divisions generating an embryo sac with seven cells: two synergid cells, one egg cell, three antipodal cells, and one central cell with a 2n nucleus. The embryo sac of Agave colimana was found to be monosporic of the Polygonum-type considered as the typical type in the majority of angiosperm plants. Also, abnormal embryo sacs were observed, following possible errors during meiosis.