Since summer in 1991, a new rust disease has occurred on leaves of potted plants of Kalanchoe blossfeldiana growing in greenhouses in Konosu, Saitama Prefecture. Dark brown pustules in lesions on the leaves were mainly composed of 2-celled teliospores, with a few 1-celled ones. Leaves of potted plants of K. blossfeldiana were artificially inoculated with basidiospores. Whitish spots appeared on the upper surface of the leaves eight to nine days after inoculation. Sixteen to 19 days after inoculation, dark brown pustules containing teliospores appeared in the lesions. The fungus was also able to infect Sedum kamtschaticum and Sedum sp. From morphological observation of the teliospores and from results of inoculation experiments, the causal fungus of the disease was identified as Puccinia benkei Kusano, a microcyclic rust. We propose ‘Sabi-byo’ and ‘Rust’ as a Japanese common name and an English common name of the new disease on Kalanchoe, respectively.