The purpose of this study is to measure the direct and indirect nursing care hours with establishment of nurse substations and compare the experimental nursing units with the existing nursing units For this study, two experimental nursing units: (1) a medical nursing unit and (2) a surgical nursing unit with a nurse substation were selected. And two control nursing units : (1) a medical nursing unit and (2) a surgical nursing unit without a nurse substation were selected. After a three-month experimental operation from June 1 to August 31,1996, research data were collected for three days from September 2 to 4, 1996. We investigated the effects of the direct & indirect nursing care hours with establishment of the nurse substations (improved nursing environment) without adding the staff nurses. The effect of establishment of the nurse sub-station was measured for the differences direct & indirect nursing care hours between experimental and control nursing units. An investigator measured the time for a staff nurse to practice each nursing activity and recorded it every minute. Percentage, average, standard deviation, t-test and ANOVA were used for data analysis. The results are as follows: 1. There was no significant difference between the experimental and control nursing units in staffs' working hours during their shift. 2. There were significant diffferences between the experimental and control nursing units in dierct nursing care hours (t=0.0288, p=0.0001) and indirect nursing care hours (t=0.3886, p=0.0103) per patient. 3. There was significant difference between the experimental and control nursing units in direct nursing care hours done by nurses(t=0.0012, p=0.0111) and aids(t=0.3011, p=0.0027). There was significant difference between the experimental and control nursing units in indirect nursing care hours done by head-nurses(t=0.0051, p=0.0253), nurses(t=0.0071, p=0.0024) and aids (t=0.3227, p=0.0351). There was significant difference between the experimental and control nursing units in indirect nursing care hours done by nurses(t=0.0005, p=0.0015) and aids(t=0.2400, p=0.0013) per patient. There was significant difference between the experimental and control nursing units in indirect nursing care hours done by head-nurses(t=0.0005, p=0.0379) and nurses (t=0.0035, p=0.0198) per patient. 4. Thre were significant differences between the experimental and control nursing units in direct nursing care hours (t=0.1134, p=0.0010) and indirect nursing care hours (t=0.7106, p=0.0008) per staff during the day shift. There were significant differences between the experimental and control nursing units in direct nunsing care hours during the day(t=0.0723, p=0.0003) and evening shift (t=0.0004, p=0.0285) per patient, and indirect nursing care hours during the day shift(t=0.5565, p=0.0036) per patient. 5. There were differences between the experiemental and control nursing units in dircet nursing activities including measurement and observation, medication, communication, teratment, hygiene, and nutrition, and in indirect nursing activities including confirmantion, communication, record, computer work, management of goods. But it was not statistically proven. 6. There was difference between the experimental and control nursing units in unmet-need nursing care hours per patient, but not statistically proven.