Antiviral sulfated steroids from the ophiuroid Ophioplocus januarii. One new and three known sulfated steroidal polyols have been isolated from the ophiuroid Ophioplocus januarii, collected at San Antonio Oeste, Río Negro, Argentina. The four compounds possess 4 alpha,11 beta-dihydroxy-3 alpha,21-disulfoxy substituents and the A/B cis ring junction but differ in the side chain. The new compound has been characterized as (22E)-5 beta-24-norcholest-22-ene-3 alpha,4 alpha,11 beta,21-tetrol 3,21-disulfate (4). The structures of the four compounds were determined from spectral data and comparison with those of related steroidal polyols. The four compounds were tested for their inhibitory effect on the replication of one DNA and three RNA viruses. Compounds 2 and 4 were active against respiratory syncytial and polio viruses, and compound 3 inhibited Junin virus, responsible for Argentine hemorrhagic fever.