BACKGROUND: Several trials have demonstrated the efficacy of nurse telephone case management for diabetes (DM) and hypertension (HTN) in academic or vertically integrated systems. Little is known about the real-world potency of these interventions. OBJECTIVE: To assess the effectiveness of nurse behavioral management of DM and HTN in community practices among patients with both diseases. DESIGN: The study was designed as a patient-level randomized controlled trial. PARTICIPANTS: Participants included adult patients with both type 2 DM and HTN who were receiving care at one of nine community fee-for-service practices. Subjects were required to have inadequately controlled DM (hemoglobin A1c [A1c]≥ 7.5 %) but could have well-controlled HTN. INTERVENTIONS: All patients received a call from a nurse experienced in DM and HTN management once every two months over a period of two years, for a total of 12 calls. Intervention patients received tailored DM-and HTN-focused behavioral content; control patients received non-tailored, non-interactive information regarding health issues unrelated to DM and HTN (e.g., skin cancer prevention). MAIN OUTCOMES AND MEASURES: Systolic blood pressure (SBP) and A1c were co-primary outcomes, measured at 6, 12, and 24 months; 24 months was the primary time point. RESULTS: Three hundred seventy-seven subjects were enrolled; 193 were randomized to intervention, 184 to control. Subjects were 55 % female and 50 % white; the mean baseline A1c was 9.1 % (SD=1 %) and mean SBP was 142 mmHg (SD=20). Eighty-two percent of scheduled interviews were conducted; 69 % of intervention patients and 70 % of control patients reached the 24-month time point. Expressing model estimated differences as (intervention -control), at 24 months, intervention patients had similar A1c [diff=0.1 %, 95 % CI (−0.3, 0.5), p=0.51] and SBP [diff=−0.9 mmH g, 95% CI (−5.4, 3.5), p=0.68] values compared to control patients. Likewise, DBP (diff=0.4 mmHg, p=0.76), weight (diff=0.3 kg, p=0.80), and physical activity levels (diff=153 MET-min/week, p=0.41) were similar between control and intervention patients. Results were also similar at the 6-and 12-month time points. CONCLUSIONS: In nine community fee-for-service practices, telephonic nurse case management did not lead to improvement in A1c or SBP. Gains seen in telephonic behavioral self-management interventions in optimal settings may not translate to the wider range of primary care settings.