Transmembrane seven helix bundles form a large family of membrane inserted receptors and are responsible for a wide range of biological functions. Experimental data suggest that their overall structure is similar to bacteriorhodopsin. We describe here a new approach for the modeling of transmembrane seven helix bundles based on statistically derived environmental preference parameters combined with experimentally determined features of the receptors. The method was used to create a model for the human beta 2-adrenoreceptor. This model is physically plausible, is in reasonable agreement with experimental data and may be helpful in planning new receptor engineering experiments.