BACKGROUND: The purposes of this study were to investigate the level of insulin injection focused self-care, in patients with diabetes mellitus, and to identify the relationship between the perceived sensitivity/severity, perceived benefits, perceived barriers, self-efficacy and situational barriers relating to the insulin injection focused self-care. METHODS: The data were collected from Type 2 diabetic patients (n=120), at an outpatients clinic of a University Hospital in Seoul, Korea, between March and May 2001. The reliability of the instrument ranged from 0.64 to 0.87 Cronbach's Alpha. The data were analyzed using the SPSS PC+, version 10.0 software: descriptive statistics were conducted for the characteristics of the sample. T-tests, Pearson correlation coefficients and multivariate multiple regression analyses were conducted to identify the associations between the cognitive-affective factors and the insulin injection focused self-care. RESULTS: 1) The average level of self-injection was 4.72+/-.45. The average of coping with hypoglycemia was 2.98 .57. The average self-monitored blood glucose was 2.83 1.15. Among these three insulin injection focused self-care activities, the average for both the coping with hypoglycemia and self-monitored blood glucose were lower than the average for self-injection. 2) The mean scores for perceived sensitivity/severity, perceived benefits, perceived barriers, self-efficacy and situational barriers were 3.32+/-.97 (range 1-5); 3.74+/-.65, 2.49+/-.76, 72.86+/-16.70 (range 10-100) and 1.10+/-.19 (range 1-4), respectively. 3) The education was significantly correlated with the insulin injection focused self-care (p=.012), but the age was not. The frequency of the self-monitoring was significantly correlated with the insulin injection-focused self-care (p=.000) and self- efficacy (p=.000). 4) The self-efficacy was significantly positively correlated with the insulin injection focused self-care (p<.01) and perceived benefits (p<.01), but negatively correlated with situational barriers (p<.05). The perceived benefits were significantly positive correlated with the insulin injection focused self-care (p<.01) and the perceived sensitivity/severity (p<.05). The perceived barriers was also significantly positively correlated with the perceived sensitivity/severity (p<.05). CONCLUSION: Our results suggest that improving the level of insulin injection focused self-care may be increased by increasing the self-efficacy, perceived benefits and perceived sensitivity/severity, and by improving the capabilities for problem solving with the situational barriers faced. Since the purposed of this study was investigate the level of insulin injection focused self-care, rather than the overall management of diabetics, there is the need to develop substantial data to support nursing interventions for the improvement of self-care in patients with diabetes mellitus.