There are a wide range of gastrointestinal nematodes, including ascarids (Toxocara, Toxascaris, and Baylisascaris spp.), hookworms (Uncinaria and Ancylostoma spp.), and whipworms (Trichuris spp.), present in companion animals across Canada, and there are strong regional differences in prevalence. Toxocara spp. ascarids are the most common GIN in pets in Canada and may pose a zoonotic risk. Because of this, most treatment and prevention guidelines target Toxocara spp. Veterinarians should conduct regular fecal diagnostic testing and follow label instructions for parasite treatment and control when approved products are available.