OBJECTIVES: To analyze association between substance abuse and quality of care in Medicare fee-for-service elderly with non-muscle invasive bladder cancer. METHODS: Retrospective case control design using SEER-Medicare databases. Non-muscle invasive bladder cancer patients diagnosed between 2001-2004 were identified. From this, we identified those with and without a diagnosis of substance abuse (ICD-9 codes: Alcohol dependence syndrome-303.xx, Drug dependence 304.xx and Non-dependent abuse of drugs 305.xx).  The groups were retrospectively followed for one year pre and five years post diagnosis. Effect of substance abuse on quality of care (ER, inpatient and outpatient visits) and cost was analyzed after adjusting for clinical and demographic variables. To compute incremental cost of non-muscle invasive bladder cancer, cancer free controls were selected (matched by age, gender, ethnicity) from Medicare. Poisson regression and GLM log-link models were used to analyze the association of substance abuse with health resource utilization and cost.  Propensity score approach was used to minimize bias.  RESULTS: A total of 33,396 patients with non-muscle invasive bladder between 2001 and 2004 we identified.  Average age was 76.7 years (std 7.2), 88% were white, 73% were male, and 61% were married.  Substance abuse prevalence was 15.96%. Compared to those no substance abuse, the substance abuse group had higher odds of ER (OR=1.56, CI=1.48-1.63), inpatient (OR=1.17, CI=1.14 - 1.19) and outpatient visits (OR=1.37, CI=1.35 – 1.39) in the one year post-dignosis period. Compared to no substance abuse group, the substance abuse group had higher total cost.We observed comparable results in the five year follow-up period. CONCLUSIONS: Substance abuse appears to affect quality of care and cost among elderly with non-muscle invasive bladder cancer. Further research is necessary to study the impact of interventions, early diagnosis and treatment of substance abuse in elderly bladder cancer patients to improve quality of care through care coordination.