We offer the first large-scale analysis of the direct link between campaign donations and lobbying — two distinct political activities that have been mostly studied separately. Using over 75 million U.S. federal lobbying reports and campaign contribution filings since 1999, we show that interest group donations are directly related to their subsequent lobbying efforts and the legislative activities of the targeted politicians. To analyze this sequential link, we use difference-in-differences estimation combined with matching, comparing firms that donate to a politician against a set of comparable firms with no donation history to the same politician. We find that donations result in an 8.5 to 10 percentage point increase in the probability that the targeted politician engages in legislative activities related to the bills lobbied by the donating firm. The estimated effects are large, short-term, and particularly pronounced for committeerelated activities. Our findings question the common perception of donations as driven either by ideology or long-term investment strategy of interest groups.