SSI disability taxable income is income may be subject to income tax. Most of the time people do not have to pay tax on their social security payments, because it is their only source of income. But there are cases where SSI disability income and earned or other income are collected. In that case the disability payments might be taxable depending on the total income received. The rules define the amount of income a person can earn while collecting social security benefits before income taxes are assessed. But only a portion of the SSI benefits are taxed with an upper limit of 85 percent established by law. The percent of SSI income that is taxable ranges from 50% to 80%. Recipients who will have to pay taxes can have them withheld from their check each month.