Chimpanzees, Pan troglodytes, help others in a variety of contexts. Some researchers have claimed that this only occurs when food is not involved and the recipient actively solicits help. In the current study, however, we found that chimpanzees often helped conspecifics obtain food in a pulling task with no solicitation whatsoever, in a situation in which, based on past experience, the conspecific's desire for the food was apparent. We also assessed whether the collaborative context of the situation impacted helping rates. Specifically, we compared how often both partners obtained rewards when one partner needed the help of the other, who had already received a reward for free (helping without collaboration), and when one partner needed the other's help after they had already begun collaborating (helping during collaboration). Partners provided assistance significantly more often in both of these helping conditions than in a control condition in which partners could provide unneeded help. However, unlike human children who have been tested in a similar task, chimpanzees did not help their partner more during (than without) collaboration. These results suggest that chimpanzees' helping behaviour is more robust than previously believed, but at the same time may have different evolutionary roots from the helping behaviour of humans.