The delivery assistance laboratory is one of the most important part of the professional curriculum in the training program for midwives. The educational significance of 10 cases of delivery assistance was reviewed. The technical standards of the students improved with accumulation of experience in the assistance of deliveries. Evaluation of the methods in which the students were assessed with regard to technical improvement in delivery assistance was performed. Of the total number of 136 students of midwifery registered at our school in the past 7years, 50 who were able to assist successively in 3-10 cases of normal childbirth were evaluated in this study with regard to their acquisition of skills needed to assist in deliveries. Fourteen technical items related to the assistance of delivery in its second and third stages were assessed. An evaluation standard consisting of 3 grades, namely "able to perform", "somehow able to perform", and "not able to perform" regarding the above mentioned 14 technical items were used to assess the mastery of delivery assistance techniques by the students. Our results showed that as the students accumulated experience in delivery assistance, self-assessment ratings of "able to perform" increased on the average. The accumulation of skill concerning the management of the neonate immediately after birth, the instruction of patients regarding the application of abdominal pressure, and the assistance during crowning was specially evident. In contrast, although self-assessment ratings of "able to perform" with regard to "assistance of the mother immediately after giving birth" and "assistance immediately after the delivery of the fetal head" did increase, its rate of increase was small.