While people often use the terms SSD/SSI interchangeably, there are some significant differences between the two federally sponsored disability programs, SSD and SSI. SSD, also known as SSDI, is the acronym for Social Security Disability Insurance, while SSD stands for Supplemental Security Income. Both are administered by the Social Security Administration; yet, the requirements and benefits differ. SSD pays benefits based on the claimant's taxes and work history. SSI is a needs-based benefit designed to supplement low income, low resource families with cash assistance. To apply for and obtain SSD, SSI and regular retirement benefits, consulting a qualified attorney is often a wise choice. To qualify for one or both of these programs, the claimant must be physically and/or mentally disabled, as certified by one or more medical professionals. Additional, the claimant must be unable to work for a minimum of twelve months or must suffer from a terminal condition.