Most of mothers place their babies in either supine or prone position without change of positi on. Studies comparing supine and prone position of the newborn infants .have already been performed with the result that the prone position is relatively better than the supine position. However, one kind of position recommended to the mothers is not sufficient for the good rearing practice of children, because the same position placed forperiod long of time may bring out physical, mental tension and fatigue, and deformities of the skull and the thorax. For this reason nurses have to find out other position which has identical or more advantages than prone position so as to perform the position change for the babies. Main purpose of this study is to identify the differences of vital signs, the number of urination, defecation, diaper rash, crying and amount of feeding of the newborn infants with prone position or lateral position during the first three days of life. Sixty two newborn infants who were delivered at Seoul National University Hospital during the period from July 1 to September 5, 1974 were chosen as subjects for this study. The criteria for the choice of subjects were the babies born with vaginal delivery; body weight 2.5kg or over at birth; Apgar score Seven or over; and gestation period between thirty-eight months and forty-two months. Of these subjects, by random sampling, thirty-one newborn infants were placed in the prone position and the other thirty-one in the lateral position. The results of this study reviewed in a statistical analysis of the t-test to obtain the following findings: 1. The heart rates of babies in the prone position were the mean heart rates of 135.03 and those in the lateral position 135.98 without any statistically significant difference. 2. There was no significant difference of respiration rate between two groups: a group in the prone position showed the mean respiration rates of 45, 57 and the other in the lateral position 46.49. 3. There was no significant difference of body temperature between two groups: the mean body temperature of a group placed in the prone position was 98degrees18'F (36degrees77'C) and that of the other group 98degrees20' F(36degrees78'C). 4. One baby showed diaper rash only in a group of infants in the prone position. 5. The number of crying of the babies in the prone position were 23.70 and those in the lateral position 30.00 with a statistical difference at 5 percent level. 6. There was no difference of frequency of urination between two groups: the mean frequency of a group placed in the prone position was 5.11 and that of the other group 5. 06. 7. There was no significant difference of frequency of defecation between two groups: the mean frequency of a group placed in the prone position was 4.20 and (hat of the other group 4.21. 8. There was no significant difference of feeding amount between two groups: the average amount of a group in the prone position showed 325.03 and that of the other group in the lateral position 291.51. All the above results mean that we may substitute the lateral position for the prone position or utilize both positions for the rearing practice of the babies.