The traditional literature regarding privatization of public enterprises under mixed oligopolies has neglected the impact of taxes. Therefore, this paper takes the effect of taxation into account and explores the optimal degree of privatization on public enterprises. It shows that, because profit taxes are non-neutral for the privatized firm, both the market equilibrium and the privatization policy will be affected by the imposition of profit taxes. Moreover, the optimal degree of privatization will increase (decrease) as tax rate increases (decreases), regardless of the number of domestic or foreign firms in the market. In other words, neglecting the impact of taxes will underestimate the optimal degree of privatization for public enterprises.