Follicle culture systems are interesting models to learn about animal and human reproductive physiology. The choice of the culture technique is based upon: the size of the ovary (the species), the developmental stage of the follicle of interest, and the duration of folliculogenesis. The success of a culture system is judged by its ability to produce developmentally competent oocyte. Until today only the mouse follicle culture is a successful system. This follicle culture model will be described. Problems associated with the large size of the ovary (human and domestic species) can be solved by culturing thin slices of tissue. Unfortunately, adult ovarian tissue is not the ideal material to attempt to develop a human follicle culture system as their follicle density is low. The stromal tissue in the ovaries of larger mammals is fibrous and dense, and therefore does not facilitate the development of a successful system for isolation and culture of follicles. More research still needs to be accomplished on small follicles. The major requirements for normal growth of follicles at the earliest stages are still unknown and must be determined if developmentally competent oocyte are to be finally obtained. Fetal ovaries are useful experimental material because of their high follicle density and the softness of the tissue. Healthy T layered follicles in culture grown from primordial fetal follicles were morphologically comparable to those grown in vivo in the vast majority of cases. However, cellular development under culture conditions might be more susceptible to genetic changes. Long-term culture could result in inappropriate cellular differentiation, genetic modification and formation of tumour cells.