The present invention relates to novel Pcr family genes which confer tolerance to heavy metals to organisms. More particularly, the present invention relates to novel Pcr family genes which confer tolerance to cadmium. Organisms transformed with any of the Pcr genes thereby have improved resistance to and increased level of toxic materials. Soil and water contaminated with heavy metals can be cleaned in an environment-friendly and economical manner by growing the Pcr-transformed organism, especially a plant transformed with the Pcr gene.