This study assessed the incidence of embryo and fetal loss following early pregnancy diagnosis using ultrasonography in dairy cows. A positive pregnancy was a recognition of the vesicle, embryo or fetus by ultrasonography. Seven hundreds and two pregnancies determined by ultrasonography following artificial insemination were divided into three groups according to the number of days diagnosed pregnant: early A group (27 to 40 days, n = 143), early B group (41 to 50 days, n = 172), or standard group (51 to 70 days, n = 387). Following a positive pregnancy diagnosis, embryo or fetal loss included all cows with observed abortions and cows found open after the positive pregnancy diagnosis. The incidence rate of embryo or fetal loss within 7 days after pregnancy diagnosis was 1.4, 0.6 and 0.3% for the early A, early B, and standard groups, respectively (P>0.05). The incidence of the embryo or fetal loss during 8 to 30 days after pregnancy diagnosis did not differ (P>0.05) among the early A (0%), early B (1.2%), and standard groups (1.0%). Furthermore, the cumulative incidence of the embryo or fetal loss before calving did not differ (P>0.05) among the early A (9.8%), early B (9.3%), and standard groups (5.9%). These results indicate that early pregnancy diagnosis using ultrasonography does not increase the risk of embryo and fetal loss compared with that of routine pregnancy diagnosis in dairy cows.