We study the probabilistic degree over R of the OR function on n variables. For ε ∈ (0, 1/3), the ε-error probabilistic degree of any Boolean function f : {0, 1} n → {0, 1} over R is the smallest non-negative integer d such that the following holds: there exists a distribution of polynomials P ∈ R[x1, . . . , xn] entirely supported on polynomials of degree at most d such that for all z ∈ {0, 1} n , we have PrPIt is known from the works of Tarui (Theoret. Comput. Sci. 1993) andBeigel, Reingold, and Spielman (Proc. 6th CCC 1991), that the ε-error probabilistic degree of the OR function is at most O(log n • log( 1 /ε)). Our first observation is that this can be improvedwhich is better for small values of ε.In all known constructions of probabilistic polynomials for the OR function (including the above improvement), the polynomials P in the support of the distribution P have the following special structure:where each Li(x1, . . . , xn) is a linear form in the variables x1, . . . , xn, i.e., the polynomial 1 − P (x) is a product of affine forms. We show that the ε-error probabilistic degree of OR when restricted to polynomials of the above form is Ω log, thus matching the above upper bound (up to polylogarithmic factors).