OBJECTIVES: Describe the prevalence, LOS, and costs  associated with MRSA in inpatients by payer status. METHODS: ICD-9 CM codes were used to identify MRSA-I (041.12) and MRSA-S (038.12) in hospital discharges in the Healthcare Costs and Utilization Project - Nationwide Inpatient Sample (HCUP-NIS) from 2009 to 2012. Charges were converted to costs using HCUP Cost-to-Charge ratio files and adjusted for inflation.  Unadjusted and multivariate adjusted LOS and costs were estimated. Unadjusted analyses by primary expected payer were performed on 2012 data. RESULTS: Hospital discharges with MRSA-I and MRSA-S were significantly older, sicker, predominantly white, male, poor and from the south compared to those without MRSA (all p-values  <0.0001).  Compared to non-infected patients, more patients with MRSA-I (7.57% vs. 5.60%), and fewer patients with MRSA-S (3.19% vs. 5.62%) did not have insurance.  Unadjusted and adjusted analyses showed significant decline in prevalence rates of MRSA-I (119.99 to 109.82) and MRSA-S (8.09 to 6.20) per 10,000 discharges. LOS was reduced for both MRSA-I (5.59 to 5.10 days) and MRSA-S (12.81 to 11.21), p<0.0005. The costs per case of MRSA-I and MRSA-S decreased slightly ($9988 to $10040, and $27955 to $26883), p=NS. Medicare beneficiaries had the highest prevalence of MRSA-I (57.2) and MRSA-S (4.09), followed by private payers (I-20.8 and S-0.91), and Medicaid (I-19.7 and S-0.84) per 10,000 discharges. However, Medicaid had both the longest LOS and highest cost for MRSA-I (I10.68 days and $23430, Medicare 9.88 and $21074, Private 8.52 and $20147) and MRSA-S (19.95 and $48554, Private 16.04 and $44922, Medicare 14.55 and $34577) in 2012 (all p<0.0001). CONCLUSIONS: Prevalence rates and LOS of MRSA-I and MRSA-S have decreased, while costs remained stable. MRSA-I and MRSA-S patients with Medicaid had higher LOS and costs than those with Medicare or private insurance, even though those with Medicare had higher prevalence rates.