This article summarizes State supplementation activities under SSI for 1975. It discusses changes in the State programs that occurred during 1975 and presents some comparisons with data for 1974--the initial year of the SSI program. A slight shift occurred in the distribution of recipients by eligibility category for Federal and State supplementation from 1974 to 1975. During 1975 a few States changed from Federal administration to State administration of their mandatory supplementation programs while a few others initiated or expanded their optional supplementation programs. Several States also increased their supplements during the year.