Pesticides and herbicides gained popularity due to a strong need to curb the starvation of billions of humans. Glyphosate is the most commonly used herbicide and was considered to be non-toxic. But its use in excess in agricultural lands has polluted soils and waters. Nowadays, glyphosate residues are found in soil, water and food. As a result glyphosate causes severe acute and chronic toxicological effects. We review toxicological effects of glyphosate and metabolites on organisms of the kingdom animalia, both unicellular and multicellular organisms. Adverse effects on unicellular organisms have been established in many experiments. For instance, glyphosate has reduced the rate of photosynthesis in Euglena, has decreased the radial growth of mycorrhizal fungal species and is also reducing the profusion of certain bacteria present in rhizospheric microbial communities. Glyphosate poses serious threat to multicellular organisms as well. Its toxicological effects have been traced from lower invertebrates to higher vertebrates. Effects have been observed in annelids (earthworms), arthropods (crustaceans and insects), mollusks, echinoderms, fish, reptiles, amphibians and birds. Toxicological effects like genotoxicity, cytotoxicity, nuclear aberration, hormonal disruption, chromosomal aberrations and DNA damage have also been observed in higher vertebrates like humans.