“Mate poaching” occurs when individuals knowingly attract someone who is already in a relationship with someone else. The current study was the first to investigate whether, to successfully attract an attached individual, the greater the degree of commitment in the individual's relationship, the greater the extent to which a poacher would need to embody desired attributes more than they are embodied by the targeted individual's partner. As predicted, 125 men and 90 women, reported that if they were to be successfully poached, the amount of wealth and attractiveness more than their current partner that a poacher would require was greater the greater the degree of commitment in their relationship. Discussion argues that relationships in which partners are of differing mate-values may be susceptible to the partner with the higher mate-value being poached by individuals who are of a higher matevalue than the other partner. Also discussed, is how the current findings might inform relationship counsellors.