Asymptotics of Penalized spline estimations Yingxing (Amy) Li Cornell University The asymptotic behavior of penalized spline estimators is studied both in the univariate and multivariate case. We use B-splines and a penalty is placed on the m-th order differences of the coefficients. The number of knots are assumed to converge to infinity faster than a minimum bound as the sample size increases and the penalty parameter plays the role of smoothing. We show that penalized splines behave similarly to Nadaraya-Watson kernel estimators. The asymptotic distribution is Gaussian and the expressions for the asymptotic mean and variance are given.