We study the relationship between foreign debt and GDP growth using a panel dataset of 122 countries from 1980 to 2015. We find that economic growth correlates positively with foreign debt and that the relationship is causal in nature by using the sovereign credit default swap spread as an instrumental variable. Moreover, using a local projection analysis we find that an increase in foreign debt leads to an increase in investment and then GDP growth in subsequent years. This indicates that foreign debt contributes to GDP growth through capital accumulation. On average, the sovereign default risk is lower and foreign debt is higher in OECD than non-OECD countries. This suggests that sovereign default risks are responsible for upstream capital flows - capital flows from poor to rich countries - that contribute to GDP growth in OECD countries. In our model foreign debt accounts at least partially for growth in OECD countries not explained by standard controls used in the growth regression literature. Foreign debt increases GDP growth by 0.4 percentage points on average accounting for 27 percent of economic growth from 1997 to 2015 in the US while it has no impact on GDP growth in China.