This paper explores the relationship between political influence activities by interest groups and benefits obtained in the form of public contracts. We propose an electoral competition model where interest groups make ex-ante campaign contributions to candidates and ex-post lobbying contributions (efforts). Campaign contributions are useful to bias the election result although an aggressive campaign fight encourages interest groups to concentrate in lobbying activities. Using a novel and unique dataset at the individual level, we find that lobbying meetings are positively correlated with public contract amount and the probability of obtaining a contract. This result holds when controlling for unobserved heterogeneity. Campaign contributions are not significantly related to either public contract amount or the probability of winning contracts.