All species of Latrodectus are venomous to humans, and their bite constitutes a medical emergency. Ordinarily, the body mass of a healthy adult is sufficient to dilute the venom to less than a fatal concentration.

Their egg sacs have distinctive shapes, textures, and colours according to the subspecies: those belonging to Black Button Spiders (Latrodectus cinctus, a.k.a. Black Widow Spiders) are smooth, cream-colored, and about the size of a pea, whereas those belonging to Brown Button Spiders (Latrodectus geometricus) are covered in small spikes.

Button Spiders weave irregularly-spaced webs with strong, elastic silk and usually include a retreat of thick, opaque silk and debris on one side.