We described the technique for the creation of the Nauplii of Balanus amphitrite amphitrite under controlled laboratory condictions, which permits observations of the moltings, the number of stages, and the characteristics of each stages. It was for the firt time that Balanus amphitrite amphitrite was reared in laboratory. From the 200 Nauplii that we obtained from the lamellae we get 120 Cypris stages, and the growth of 78 young balanids. Cyclotella nana from the New York Aquarium culture was used for alimentation. The larval phase of Balanus amphitrite amphitrite consiste of six naupliar stages and one Cypris stage. Form and size of the body, the number and structure of the appendage settation and spines, are given for all the larval stages. There are described all details of the microanatomy of each stage. The setation is, however, a valuable criterion for the identification of the Nauplii and may be used to separate stages and species. The duration of the six stages are the followings; first stage: 15 to 20 minutes; second stage: from the 2th to 4th day; third stage; from the 4th day to 6th; fourth stage: up to 8th day; fifth stage: from the 9th to 11th day and the sixth stage: up to the 12th day. The necessary time for the complete larval development in laboratory of Balanus amphitrite amphitrite ranges from 12 to 14 days. We continued to observe and study the Cypris stages metamorphose in young balanids and their growth for more than 3 months in the glass criation.