This article presents a study of ethnic Differential Item Functioning (DIF) for 4th-, 7th-, and 10th-grade reading items on a state criterion-referenced achievement test. The tests, administered 1997 to 2001, were composed of multiple-choice and constructed-response items. Item performance by focal groups (i.e., students from Asian/Pacific Island, Black/African American, Native American, and Latino/Hispanic origins) were compared with the performance of White students using simultaneous item bias and Rasch procedures. Flagged multiple-choice items generally favored White students, whereas flagged constructed-response items generally favored students from Asian/Pacific Islander, Black/African American, and Latino/Hispanic origins. Content analysis of flagged reading items showed that positively and negatively flagged items typically measured inference, interpretation, or analysis of text in multiple-choice and constructed-response formats. Items that were not flagged for DIF generally measured very easy reading skills (e.g., literal comprehension) and reading skills that require higher level thinking (e.g., developing interpretations across texts and analyzing graphic elements). (Contains 7 footnotes, 11 tables and 3 figures.)