Adult Norway rats (Rattus norvegicus) frequently groom each other. Grooming social partners is an altruistic act imposing costs to donors and benefits to recipients. Here, we tested whether rats trade this cooperative behaviour reciprocally among each other, and whether the relative rank in the social hierarchy influences their grooming propensity. Hitherto, studies of reciprocal allogrooming typically relied on correlative observational data. By manipulating grooming rates experimentally, we show that (i) rats groom each other reciprocally following tit-for-tat like decision rules and (ii) rats allogroom preferentially up the hierarchy. In a second experiment, we tested whether rats would use different behavioural mechanisms to exchange food among each other. Rats could either pull food into reach of a social partner or to push a lever to release food for the partner. In both situations, the donor did not receive food herself, so the helpful act was again altruistic. We asked whether rats receiving food from the partner by one mechanism (e.g. pulling) would return the favour subsequently by transferring the task to a different effort (e.g. pushing). Our data show that indeed, rats transfer the task between receipt and delivery of help. Finally, we present results of an experiment where rats were able to transfer received help (e.g. by being groomed) to a different commodity (e.g. delivery of food). Overall, our results demonstrate experimentally that Norway rats trade services reciprocally among each other in a wide range of conditions, which has not been shown yet in any other animal.