We investigated morphological and molecular diversity within cultivated common bean (Phaseolus vulgaris L.) in Switzerland and examined the origin of Swiss cultivars. We considered commercially traded cultivars and elder cultivars. These elder cultivars, often called landraces, collected and kept on farm by the Swiss non-governmental organisation Pro Specie Rara, are supposed to represent an endangered heritage of diversity within common bean. Morphological characters, phaseolin Sodium Dodecyl Sulfate Polyacrylamid gel-electrophoresis (SDS-PAGE), isoenzymes, and banding patterns of Random Amplified Polymorphic DNA (RAPD) showed polymorphisms and diversity among Swiss common bean cultivars. Cultivars were characterised either by the S-type or the T-type of the major storage protein phaseolin. This indicates that some Swiss cultivars have Mesoamerican origin while others have Andean origin. This hypothesis is corroborated by the Unweighted Pair Group Measured Analysis (UPGMA) clustering of the cultivars with a combined set of morphological, phaseolin, isoenzyme and RAPD data. A better knowledge of genetic and phenotypic aspects of the common bean helps to improve conservation programs for its endangered cultivars.