The purpose of this cross-sectional, descriptive, correlational study was to describe the relationships among demographic factors (age, gender, education, income), perceived severity of illness, perceived barriers to action, perceived self-efficacy, and interpersonal influences (social support) and health-promoting behaviors (HPB) and to identify predictors of HPB. A nonprobability sample of 110 participants with Chronic Renal Failure (CRF) was recruited from the outpatient clinic of Burirum hospital and Surin hospital located in north-eastern Thailand. All participants were individually interviewed by the principal investigator in a private area within an outpatient clinic. Six variables were significantly correlated with the HPB. They were age, education, perceived severity of illness, perceived barriers to action, perceived self-efficacy and social support. According to the results from the analyses of demographic data and HPB, participants who were younger and had higher educational levels practiced more HPB. From the analyses of perceived severity of illness, perceived barriers to action, perceived self-efficacy, and social support and HPB, the results showed that participants with lower levels of perceived severity of illness and lower levels of perceived barriers to action reported better HPB. In contrast, the participants with higher levels of perceived self-efficacy and social support reported better HPB. By using a stepwise multiple regression analysis, two predictors were identified from 8 predictor variables, and those two accounted for 78.2% (p < 0.01) of the variance in HPB. Two variables that contributed significantly to the variance in the HPB were perceived self-efficacy ([beta] =.769, p < 0.01), and social support ([beta] = .162, p < 0.01); whereas age, gender, income, educational level, perceived severity of illness, and perceived barriers did not contribute to the variance in the HPB. The study found that participants who experienced better perceived self-efficacy and social support reported better HPB. In contrast age, gender, income, educational level, perceived severity of illness, and perceived barriers did not enter as predictors in this stepwise regression equation. / text