Introduction The * Equal contributors. health-status of heart failure patients can be improved to some extent by disease self-management. One method of developing such skills is telephone-based health coaching. However, the effects of telephone-based health coaching remain inconclusive. The aim of this study was to evaluate the effects of telephone-based health coaching for people with heart failure. Methods A total sample of 7186 patients with various chronic diseases was randomly assigned to either the coaching or the control group. Then 184 patients with heart failure were selected by International Classification of Diseases (ICD)-10 code for subgroup analysis. Data were collected at 24 and 48 months after the beginning of the coaching. The primary outcome was change in quality of life. Secondary outcomes were changes in depression and anxiety, health-related control beliefs, control preference, health risk behaviour and health-related behaviours. Statistical analyses included a per-protocol evaluation, employing analysis of variance and analysis of covariance (ANCOVA) as well as Mann-Whitney U tests. Results Participants' average age was 73 years (standard deviation (SD) = 9) and the majority were women (52.8%). In ANCOVA analyses there were no significant differences between groups for the change in quality of life (QoL) However, the coaching group reported a significantly higher level of physical activity ( p = 0.03), lower intake of non-prescribed drugs ( p = 0.04) and lower levels of stress ( p = 0.02) than the control group. Mann-Whitney U tests showed a different external locus of control ( p = 0.014), and higher reduction in unhealthy nutrition ( p = 0.019), physical inactivity ( p = 0.004) and stress ( p = 0.028). Discussion Our results suggest that telephone-based health coaching has no effect on QoL, anxiety and depression of heart failure patients, but helps in improving certain risk behaviours and changes the locus of control to be more externalised.