Abstract.In this paper the Christoffel numbers av n for ultraspherical weight functions wk , wx(x) = (\ -x ) ~ ' , are investigated. Using only elementary functions, we state new inequalities, monotonicity properties and asymptotic approximations, which improve several known results. In particular, denoting by dv " the trigonometric representation of the Gaussian nodes, we obtain for À e [0, 1] the inequalities and similar results for X <£ (0, 1). Furthermore, assuming that a\ ' remains in a fixed closed interval, lying in the interior of (0, n) as n -► oo , we show that, for every fixed A > -1/2 ,