We analyze the effect of investments in corporate social responsibility (CSR) on workers’ motivation. In our experiment, a gift exchange game variant, CSR is captured by donating a certain share of a firm’s profit to charity. We are testing for CSR effects by varying the possible share of profits given to charity. Additionally, we investigate the effect of matching mission preferences, i.e., a worker preferring the same charity the firm donates to. Our results show that, on average, workers reciprocate investments in CSR with increased effort. Matching mission preferences also result in higher effort, independently of the extent of the CSR investment.