This study describes the ovary anatomy and dynamics of oocytes maturation process of Amblyomma brasiliense ticks. The ovary is of panoistic type lacking nurse and follicular cells. This organ consists of a single continuous tubular structure comprising a lumen delimited by the ovarian wall. Oocytes of this tick species are classified into five stages (I-V) and described based on cytoplasm appearance, presence of germ vesicle, yolk granules aspects, and chorium deposition. Oocytes of various sizes and at different developmental stages remain attached to the ovary by a cellular pedicel until completing stage V. Then they are released into the ovary lumen and from there into the exterior.