This article is concerned with the existence result of the unilateral problem associated to equations of the type Au + g(x, u,<FONT FACE=Symbol>Ñ</FONT>u) = f, in Orlicz spaces, where f <FONT FACE=Symbol>Î</FONT>L¹(omega), the term g is a nonlinearity having natural growth and satisfying the sign condition. Some stability and positivity properties of solutions are proved