OBJECTIVES: Projecting total joint arthroplasty (TJA) demand is important for policy decisions that affect physician supply and patient access. Using a linear model, Kurtz et al. (2007) projected that demand for total knee arthroplasty (TKA) and total hip arthroplasty (THA) would increase by 673% (to 3.4 million procedures) and 174% (to 572,000 procedures), respectively, by 2030. The purpose of this study was to re-examine future TJA demand utilizing current data, with linear and exponential growth models. METHODS: Nationwide Inpatient Sample data (2003-2012) was used to obtain patient demographic data and weighted, annual TKA and THA prevalence. United States Census Bureau data were used to obtain historical and future population estimates. Ordinary least squares (OLS) regression models were used with NIS prevalence data to determine linear projections. Poisson regression models with census data were used to estimate an exponentiated number of TJA procedures. Comparisons were made between historical projections, current linear and exponentiated projections and actual, weighted national estimates. RESULTS: We projected 2010 TKA demand between 515,615 (exponentiated model) and 520,939 (linear model) with an increased demand in 2030 between 1,300,059 (150% increase, linear model) and 4,475,729 (768% increase, exponentiated model). The national weighted 2010 TKA prevalence was 545,156, which is slightly higher than projected. We projected 2010 THA demand between 243,443 (exponentiated model) and 245,668 (linear model) with an increased demand in 2030 between 524,676 (116% increase, exponentiated model) and 603,908 (146% increase, linear model). The national weighted 2010 THA prevalence was 251,504, which is slightly higher than projected. CONCLUSIONS: The historical (Kurtz, et al) and current models are similar to the actual 2010 TJA prevalence. However, 2030 estimates vary considerably between the three projection models. Estimating future TJA demand is complex. Regardless of statistical methodology, TJA demand is increasing and impacting patient access to care.