Dr. Dae-Jin Lee BCAM – Basque Center of Applied Mathematics.Non-parametric regression or smoothing is a form of regression analysis in which the predictor does not take a predetermined form but is constructed according to information derived from the data. There is a wide range of smoothing techniques in the literature, penalized splines are a very popular tool for smoothing due to their flexibility and ability to incorporate more complex structures such as additional covariates, correlations or hierarchical structures and multidimensional settings. In this talk I will introduce some basic concepts and techniques together with several examples from environmental and ecological applications.