21 amber-ochre supersuppressor alleles have been isolated in a strain of Saccharomyces cerevisiae. Their dominance-recessiveness, temperature sensitivity, allelism, intergenic and intragenic complementation properties and their effect on cell viability and colony growth rate have been characterized. They are compared with the yeast amber-ochre supersuppressors described by Inge-Vechtomov and Andrianova (1970a, b) and Hawthorne and Leupold (1974). The possible molecular basis of their suppressor activity is discussed in relation to their genetic properties.