Among patients with a chronic disease, low adherence to prescribed treatments is very common, leading to substantial morbidity, mortality, and increase in health care costs. Telephone or mobile phone support is a common form of intervention that can be used to improve their adherence. We reviewed existing systematic and nonsystematic reviews to analyze the effectiveness of telephone interventions to improve treatment adherence in patients with chronic disease. Secondary aims were to evaluate the selected reviews in terms of cost-effectiveness of the intervention and frequency of messages affecting the adherence outcomes. A search for reviews was conducted in three databases, including PubMed, the Cochrane Library, and CINAHL, and three reviews that met the inclusion criteria were selected for final analysis. A qualitative review of the selected reviews was conducted, and reviews were evaluated to extract and summarize the characteristics and outcomes. Two of the selected reviews studied mobile phone text messaging, and one review studied telephone or mobile phone consultation. All three reviews reported an overall improvement in adherence, but the reviews varied in the types of research and the outcome measures. However, none of the reviews reported costs as an outcome. The evidence from reviews to characterize the effectiveness or cost-effectiveness of telephone support as an intervention to improve adherence among people with chronic diseases is fairly small and weak. Telephone support interventions have to be evaluated more systematically in routine practice against a comprehensive set of criteria, including their relative costs and outcomes.