Publisher Summary The chapter presents implicit viscoelastic calculations using Brownian configuration fields. An implementation of the implicit time integration of micro-macro problems based on the Brownian configuration fields for complex flows has been presented for the first time. A novel size reduction method is presented to deal with the large size of the linear systems under consideration. The algorithm allows an independent treatment for each molecular field and is well suited to parallel hardware architecture. The method is tested on well known benchmark problems for viscoelastic flows, and the results compare very favorably with obtainable analytical expressions. An extensive comparison, in terms of efficiency, stability and accuracy, between the different methods to solve time dependent problems based on the micro-macro idea is of paramount importance in order to select which features of each algorithm are interesting and, perhaps, design a better numerical scheme based on the combination of them.