Public-private partnerships are used to procure public infrastructure. Despite involving private investors and concessionaires, they impact the public budget like traditional provision and create fiscal risks. This paper develops a conceptual framework to assess whether and how public-private partnerships shift risks to concessionaires and financiers. It uses this framework to describe and assess the Chilean public-private partnerships program. The paper identifies renegotiations as the major source of fiscal risk, which involved additional investments, increasing the cost by about one-third over the original project cost estimates. The 2010 law reform on public-private partnerships introduced changes to the renegotiations regime and began the routine use of variable term contracts. Using contractual data, the analysis finds evidence suggesting that renegotiations fell dramatically. The paper also calculates the realized internal rates of return for 50 highway and airport public-private partnerships, using cash flow data for the entire public-private partnerships program, which started in 1991. The average internal rate of return is 6.8 percent, with averages of 9.1 and 3.1 percent for fixed and variable term public-private partnerships, respectively. The returns show a large dispersion, which suggests that infrastructure projects are intrinsically risky and private participation entails significant risk shifting from the budget to concessionaires and financiers.