This paper describes how to use multi-level models for longitudinal studies with panel data. A special focus is set on the specification and estimation of hybrid models combining some advantages of models for fixed-effect and random-effects panel regression. The paper addresses some basic principles of multi-level- and panel analysis but it also discusses some very special problems of longitudinal analysis like centering of variables. It presents an example of a stepwise, applied panel regression analysis within a multi-level-model approach using the data of the SOEP (the national German socio-economic panel study) and the SPSS-MIXED-software. After reading this paper every social research scholar should be able to perform his/her first longitudinal analysis by multi-level modeling.