AbstractUp to now, more than 500 extra-solar planets have been discovered. Many of these extrasolar systems consist of one star and only one giant planet. However, recently more and more different types of systems have become known, including also extrasolar planets in binaries. In our study, we will concentrate on such systems, since a large percentage of all G-M stars are expected to be part of binary or multiple stellar systems. Therefore, these kinds of systems are worthy of investigation in detail. In particular, we will concentrate on planets in P-Type motion, where the planet orbits around both stars. During the last few years, four such systems (NN Ser, HW Vir, HU Aqr and DP Leo) have been discovered. In our study, we performed dynamical studies for three multi-planetary systems in binaries (NN Ser, HW Vir, HU Aqr), and compared simulated eclipse timing variations (ETV) to current observational data.