State income tax laws and their relationship to the federal income tax were surveyed and changes affecting forest landowners since similar research on this subject (1981-82) are discussed. Several previously favorable provisions were eliminated at the federal level. Although the economic situation and research assumptions have changed, the general indications are that many states have implemented provisions which may be considered generally unfavorable to forest landowners. The 1988 federal and state income tax liabilities for hypothetical forest landowners at three personal income levels, each with and without timber sale revenue, were calculated for 41 states in the U.S. which impose a comprehensive income tax. In the South, the state percentage of the total income tax liability for the hypothetical landowners who sell timber ranged from 9 to 21, 7 to 17, and 6 to 15 percent for the low, medium and high income levels, respectively. The state percentage ranged from 10 to 31, 9 to 20, and 7 to 16 percent for the low, medium and high income levels, respectively for landowners who did not sell timber. Louisiana was the lowest and North Carolina was the highest for all hypothetical cases. In the West, the state percentage ranged from 13 to 25, 12 to 25, and 10 to 19 percent, for the low, medium and high income levels, respectively, for landowners who sold timber. The state percentage for landowners who did not sell timber ranged from 10 to 34, 15 to 25, and from 12 to 20 percent the low, medium and high income levels, respectively. Arizona and Colorado consistently were among the lowest and Hawaii was the highest for all the hypothetical cases / Master of Science