Sea anemones produce a myriad of toxic peptides and proteins of which a large group acts on voltage-gated Na(+) channels. However, in comparison to other organisms, their venoms and toxins are poorly studied. Most of the known voltage-gated Na(+) channel toxins isolated from sea anemone venoms act on neurotoxin receptor site 3 and inhibit the inactivation of these channels. Furthermore, it seems that most of these toxins have a distinct preference for crustaceans. Given the close evolutionary relationship between crustaceans and insects, it is not surprising that sea anemone toxins also profoundly affect insect voltage-gated Na(+) channels, which constitutes the scope of this review. For this reason, these peptides can be considered as insecticidal lead compounds in the development of insecticides.