Objective and Background: The decision regarding elective cholecystectomy in older patients with symptomatic cholelithiasis is complicated. We developed and validated a prognostic nomogram to guide shared decision making for these patients. Methods: We used Medicare claims (1996-2005) to identify the first episode of symptomatic cholelithiasis in patients older than 65 years who did not undergo hospitalization or elective cholecystectomy within 2.5 months of the episode. We described current patterns of care and modeled their risk of emergent gallstone-related hospitalization or cholecystectomy at 2 years. Model discrimination and calibration were assessed using a random split sample of patients. Results: We identified 92,436 patients who presented to the emergency department (8.3%) or physician's office (91.7%) and who were not immediately admitted. The diagnosis for the initial episode was biliary colic/dyskinesia (65.3%), acute cholecystitis (26.6%), choledocholithiasis (5.7%), or gallstone pancreatitis (2.4%). The 2-year emergent gallstone-related hospitalization rate was 11.1%, with associated in-hospital morbidity andmortality rates of 56.5% and 6.5%. Factors associated with gallstone-related acute hospitalization included male sex, increased age, fewer comorbid conditions, complicated biliary disease on initial presentation, and initial presentation to the emergency department. Our model was well calibrated and identified 51% of patients with a risk less than 10% for 2-year complications and 5.4% with a risk more than 40% (C statistic, 0.69; 95% confidence interval, 0.63-0.75). Conclusions: Surgeons can use this prognostic nomogram to accurately provide patients with their 2-year risk of developing gallstone-related complications, allowing patients and physicians to make informed decisions in the context of their symptom severity and its impact on their quality of life.