The Brazilian, who arrived in Tehran, Iran Sunday night, has penned a one-year contract with Persepolis.
Born in Passo Fundo, Rio Grande do Sul, Loss began his career with Internacional's youth setup in 1994.
Osmar Loss has coached Brazilian football clubs Corinthians, Guarani and Vitória.
Osmar has replaced Hamid Motahari who left Persepolis to lead Nassaji.