The studies on the behavior of spermatozoa in the oviduct of the hen are important in order to clear the mechanism of retention for a long period of the fertilizing capacity of spermatozoa in the oviduct.In the previous papers, the author stated that the inseminated spermatozoa were retained in the glandular cavities (sperm-nests) of both the infundibulum and the utero-vaginal junction, and the infundibulum probably had higher capacity for the preservation of spermatozoa than the utero-vaginal junction.This paper describes the results concerning the fertility and spermatozoal behavior following infundibulal and vaginal inseminations, and the estimation concerning the difference in the capacity for the preservation of spermatozoa between the infundibulum and the utero-vaginal junction.1) Inseminations of one hundred million spermatozoa were made in two sites; the infundibulum following laparotomy and the vagina. The weekly percentages of fertile eggs during three weeks following inseminations were respectively, 93.8, 88.2, 33.0 in the case of the infundibulum; 87.5, 50.0, 7.2 in the case of the vagina. The duration of fertility following the infundibulal insemination ranged over 12 to 27 days, with a mean of 17.2 with a S.D. of 4.0 days. On the other hand, when the insemination was made in the vagina, it ranged over 6 to 17 days, with a mean of 12.2 with a SD. of 3.5 days.There appeared at 2nd week significant differences in percentages of fertile eggs following the infundibulal and vaginal inseminations, and so did they at 3rd week. And the durations of fertilities in the two cases of inseminations were different significantly.2) Histological evidence showed that spermatozoa deposited in the infundibulum entered the infundibulal glands (sperm-nests) in all examples, but some spermatozoa migrated caudally and entered the utero-vaginal glands (sperm-nests) in several examples.3) There were no significant difference in the percentages of fertile eggs and in the durations of fertilities following vaginal inseminations between one hundred million spermatozoa and larger numbers (four hundred million and one thousand million spermatozoa).4) The results in this paper and the previous papers showed that most spermatozoa deposited in the infundibulum were preserved in the glands (sperm-nests) of this portion and most spermatozoa deposited in the vagina were preserved in the utero-vaginal glands (sperm-nests).5) It seems likely that the significant differences in the percentages of fertile eggs and in the durations of fertilities between the infundibulal and the vaginal insemination were owing to the difference of the capacity for the preservation between the infundibulal and utero-vaginal glands (sperm-nests).