The high prevalence of Toxocara in cats, dogs and foxes results in the contamination of soil with infective eggs of Toxocara spp. which are found in soil samples from public and private places worldwide. In Poland the most contaminated areas were city backyards where 38–53% of soil samples were positive, especially in the spring. Human exposure to infection with Toxocara spp. was proportional to the prevalence of eggs in the samples examined but soil texture was not a critical factor in the degree of soil contamination. Eggs of Toxocara spp. placed on the ground penetrated a sand soil profile slowly. Their presence in the superficial layer of soils and the role of earthworms are instrumental in the dissemination of Toxocara eggs.