The purpose of this paper is to describe the early introduction protocols developed for four (1.3) hand-reared Gorillas Gorilla gorilla that were introduced to conspecifics at Barcelona Zoo. The introduction process for each was initiated when the infants were <1 year old. The introductions began in 1999 and ended in 2001, and the difficulties faced while carrying out such procedures were novel at that time. The protocols had to be improved following the assay error results. In the first instance, the infant Gorillas were introduced into their family group of two hand-reared adult ♀♀ and a silverback. However, the development conditions and rearing inexperience of the adult ♀♀ resulted in failure to nurture the young. The ♀♀ did not protect or take care of the infants well enough to keep them safe. Appropriate maternal behaviours did not develop in the adults, although some social contacts between the adults and young were observed during the process. However, a silverback managed to kill a 6 month-old ♂ infant after a slide-gate malfunction. The three ♀ infants were successfully integrated into a group of conspecifics but not into their family group.