Objective: To determine whether a clinician-led chronic disease self-management support (CDSMS) program improves the overall self-rated health level of older Australians with multiple chronic health conditions. Design: Randomised controlled trial: participants were allocated to a clinician-led CDSMS group (including client-centred goal setting and the development of individualised care plans) or to a control group in which they received positive attention only. Setting and participants: Patients aged 60 years or more with at least two chronic conditions, recruited between September 2009 and June 2010 from five general practices in Adelaide. Main outcome measures: The primary outcome was self-rated health. Secondary outcome measures related to health status (fatigue, pain, health distress, energy, depression, illness intrusiveness), health behaviour (exercise, medication adherence), and health service utilisation. Results: 254 participants were randomised to the CDSMS and control groups, of whom 231 (117 control and 114 CDSMS participants) completed the 6-month programs and provided complete outcomes data (91%). An intention-to-treat analysis found that CDSMS participants were more likely than control participants to report improved self-rated health at 6 months (odds ratio, 2.50; 95% confidence interval, 1.13–5.50; P = 0.023). Between-group differences for secondary outcomes were not statistically significant. Conclusion: CDSMS may benefit some older people with multiple chronic conditions to a greater extent than positive attention and health education. Trial registration: Australian New Zealand Clinical Trials Registry ACTRN12609000726257.