Contrail Cirrus Prediction model CoCiP is coupled to the ECMWF's Integrated Forecast System (IFS). CoCiP is a trajectory model, simulating individual contrails. It is being coupled to the numerical weather prediction model using OpenIFS (model cycle 38r1) in medium resolution T159 and serial mode. The new online CoCiP is exchanging the tendency of specific humidity with the IFS. The coupled version, CoCiP-IFS, runs stably and CoCiP output parameters show reasonable results. The coupling improves the supply of input data for CoCiP. This leads to contrail cirrus predictions free from artificial oscillations. An effect of the coupling onto the IFS could not be distinguished from random noise within the scope of this thesis.