Abstract: In order to clarify the prevalence and clinical features of so-called “maternity blues” and the relationship with depression after delivery, we conducted a prospective study on 220 mothers using the Zung's Self-Rating Depression Scale (ZSDS) 4–7 days after childbirth and again one month after childbirth. Their physical condition during their pregnancy had been evaluated earlier. As in a previous epidemiological study conducted in Japan, we classified subjects with a ZSDS score of 60 and over as a high scoring group. Eighteen mothers (8.18%) fell into this group (“maternity blues” group) in the one week post-partum evaluation. Comparing the ZSDS scores one month after childbirth with the earlier scores, in 10 women (4.5%), their scores decreased from 60 and over to below 60 (a “maternity bines” core group), and in 8 women (3.6%), their scores were still over 60 (a prolonged “maternity blues” group). Eleven (5.0%) out of the 202 women whose scores at one week after childbirth were below 60 showed a high score (60 and over) one month after childbirth (a potential depression group). All in, 191 women scored below 60 in both evaluations. Although we could divide the subjects into 4 groups as described above, we could not find any clinical symptoms to distinguish between the 3 groups with “maternity blues” or depression in the evaluation one week after childbirth. However, one finding suggests that these three groups may have different features.