Support has always been considered an important nursing concept. However, there is no agreement among nurse researchers as to a conceptual definition of supportive nursing or meaningful supportive behaviors. Clarification of the concept, support in nursing, is necessary to promote communication among nurses on nursing behaviors that are effective in providing support and on understanding the relevant properties and charcteristics of the concept, supportive nursing care. The objectives of the study were : 1. to analyse the concept, support in nursing, in order to provide a definition of supportive nursing care, and 2. to operationalize the definition of supportive nursing care and use it as an experimental nursing intervention for patients with low back pain. The first part of the study used the concept analysis approach developed by Walker and Avant(1983) to define the concept of supportive nursing care. The properties of supportive nursing care, defined by this analysis, included perception of supportive need, reciprocal interaction(Transaction), listening, providing empathy and information related to health, and confirmation of the patient's verbal and non - verbal response. The second part, the experimental part of the study, was done using King's(1970) Interpersonal Theory for Nursing. The concept, supportive nursing care, as defined in the concept analysis was operationalized and used as the experimental intervention. The experiment tested the effectiveness of the independent variable, supportive nursing care on the dependent variables, depression, mood and patient satisfaction, in the patients with low back pain in army hospitals. The instruments used to measure the dependent variables were Zung's(1965) Self- Rating Depression Scale, Ryman and Colleagues'(1974) Mood Questionnaire and LaMonica and Colleagues'(1986) Patient Satisfaction Scale. The experimental design used for this study was a Solomon 4 group experimental design. This design has the strength of allowing for observation of the main effects of supportive nursing care and pretesting, and for observation of the interaction effects of pretesting and supportive nursing care. The design includes one experimental group and three control groups. The Subjects of this study were 150 young male patients with low back pain on Neuro - Surgical Wards in three general army hospitals. There were 35 in the experimental group, 39 in the pre - posttest control group, 36 in the treatment - posttest control group and 40 in the posttest only control group. Supportive nursing care, as operationalized by the researcher according to the concept analysis, was given to the patients in the experimental group and the treatment -posttest control group, individually for 30 minute sessions, every other day for 5 days. Data collection was done using a questionnaire. The data were collected in a pretest one week before the supportive nursing care sessions, a posttest immediately after the sessions and follow- up test one week later. Hypotheses testing was done using 2×2 factorial analysis of variance and Meta analysis(Stouffer's Z method). The results of this study are summarized as follows : 1. Hypothesis Ⅰ, “There will be a difference on depression level between the patients with low back pain who receive supportive nursing care and those who do not receive supportive nursing care”, was supported (F＝8.49, p＜.05). 2. Hypothesis Ⅱ, “There will be a difference on mood level between the patients with low back pain who receive supportive nursing care and those who to not receive supportive nursing care”, was supported (Z meta＝2.17, p＜.05). 3. Hypothesis Ⅲ, “There will be a difference on satisfaction level between the patients with low back pain who receive supportive nursing care and those who do not receive supportive nursing care”, was supported (F＝13.67, p＜.05). 4. ANOVA, done to examine the interaction effect of history and maturation, showed no significant difference on the dependent variables between the observations of the pretest scores of the experimental group, the pretest scores of the pre- posttest control group and the posttest score of the posttest only control group. 5. To test for continuing effect of supportive nursing care, paired t-test was done to compare the scores for the dependent variables at the posttest and at the one week later follow-up test. No significant difference on the scores for the dependent variables was found between the posttest scores and the follow-up test scores for the two groups that received supportive nursing care, the experimental group and the treatment-posttest control group. In conclusion, it was found that in the case of young soldiers with low back pain in army hospitals, their depression level was decreased, their mood state was changed positively and their satisfaction level was increased by receiving supportive nursing care. Further, the effectiveness of the supportive nursing care lasted for at least one week in this study. The significance of this study to nursing is in the analysis of the concept of supportive nursing care and the demonstration of the effectiveness of supportive nursing care as an intervention within the limits of the study.