This was a study of differential item functioning (DIF) for grades 4, 7, and 10 reading and mathematics items from state criterion-referenced tests. The tests were composed of multiple-choice and constructed-response items. Gender DIF was investigated using POLYSIBTEST and a Rasch procedure. The Rasch procedure flagged more items for DIF than did the simultaneous item bias procedure--particularly multiple-choice items. For both reading and mathematics tests, multiple-choice items generally favored males while constructed-response items generally favored females. Content analyses showed that flagged reading items typically measured text interpretations or implied meanings; males tended to benefit from items that asked them to identify reasonable interpretations and analyses of informational text. Most items that favored females asked students to make their own interpretations and analyses, of both literary and informational text, supported by text-based evidence. Content analysis of mathematics items showed that items favoring males measured geometry, probability, and algebra. Mathematics items favoring females measured statistical interpretations, multistep problem solving, and mathematical reasoning. (Contains 8 tables, 2 figures, and 4 footnotes.)