Pythiosis caused by Pythium insidiosum, is an emerging, life threatening infectious oomycetic disease of humans, and animals. Among several species of animals, equine is the main species affected by this oomycete. Disease can occur in sporadic and epidemic form, and has been reported from many counties of the world. The source of infection is exogenous. It is believed that humans,and animals acquire the infection from the aquatic environment where the organism live as a saprobe. Hence, pythiosis can be considered as a waterborne parafungal disease. In humans, various forms of disease including ocular, vascular, systemic,and cutaneous/subcutaneous are observed. Vascular and ocular pythiosis are the most common forms of the infection, accounting for about 95 % of cases. In equines, pythiosis is characterized by the formation of irregular masses within the cutaneous lesions, called kunkers. Microbiological, histopathological, immunological, and molecular techniques are employed to diagnosis the disease. The conventional antifungal drugs are ineffective for the treatment of pythiosis, because Pythium species may lack the drug-target ergosterol. Recently, a new group of antifungal drugs such as caspofungin, micafungin, or anidulafungin may be effective in the treatment of pythiosis. The immunotherapeutic vaccine is another treatment option because the favourable outcomes were observed in some patients and animals. However, the vaccine efficacy is usually limited. Pythiosis is an occupational disease of fisherman, agricultural farmers, livestock handlers, and others who work in aquatic environment. Patients should be educated to prevent themselves from the direct skin inoculation of the organism by wearing boots when working outdoors. As prognosis is guarded, timely recognition, and treatment are highly imperative for successful management of pythiosis. Furthermore, understanding the route of infection and pathogensis of P.insidiosum infection can help in the control of disease both in humans as well as in animals. More research is warranted on the development of safe, cheap, and potent chemotherapeutic and immunoprophylactic agents to combat pythisosis in humans and animals.