In this publication, Philippe Doyen reviews some of the most widely used workflows for constraining 3-D earth models with seismic data. They typically involve a sequential process where seismic data are first inverted to elastic properties. Inverted data are then depth-converted and transferred into the earth model framework, where the seismic attributes are used to guide the interpolation of reservoir properties between the wells.Geostatistics provides a number of tools for this purpose, including generalized regression techniques such as cokriging and kriging with external drift, stochastic simulation with seismic constraints and geostatistical inversion. These techniques are reasonably well-established and their application can lead to significantly better constrained earth models. So what are the remaining challenges for seismic data integration in earth models? In particular, what are the main limitations or bottlenecks with current approaches that need to be addressed in order to make this integration more widely applicable? In the last few paragraphs, Philippe Doyen lists some of the future challenges and new directions in seismic earth modelling.