A macroeconomic disequilibrium model is developed for theFederal Republic of Germany. Starting with a microeconomicmodel of firm's behaviour, the optimal dynamic adjustment ofemployment and investment is derived. The model of the firmis complemented by an explicite aggregation procedure whichallows to derive macroeconomic relations. The model isestimated with macroeconomic data for the Federal Republicof Germany.An important feature is the consistent introduction ofdynamic adjustment into a model of the firm. A new method isthe particular approach of a delayed adjustment ofemployment and investment.The estimation results show significant underutilizations oflabour and capital and indicate the importance of supplyconstraints for imports and exports. As the most prominentresult, they reveal the importance of the slow adjustment ofemployment and investment for the macroeconomic situation inGermany and especially for the persistence of highunemployment in the eighties.