Previous research has shown that altruism is an important trait in romantic relationships, particularly longer relationships were it can signal underlying characteristics (e.g. kindness) that are valued in good partners/parents. Further evidence of this has been observed when comparing the interaction between altruism and other traits (e.g. physical attractiveness) that may signal other qualities (e.g. good genes), where altruism was preferred by heterosexual women in long-term partners. To further explore the role of altruism in relationships and its interaction with other mate choice traits, the current study examined heterosexual women’s preferences for altruism and a trait signalling good investment, that of resource potential. Here we found that, as predicted, women preferred altruistic male partners for long-term relationships, and that altruism was a more desired trait than resource potential in potential long-term partners. These findings support the view that altruism is a high valued trait in relationship formation due to it signalling good partner/parent indicators., and is more important than resource potential when women choose long-term partners.