This study compared end-of-year standardized test scores (CAT) of 204 children in 6 developmentally appropriate and 6 developmentally inappropriate kindergarten classes. Particular attention was given to the effects on test scores of the interaction of classroom type with sex, socioeconomic status, and race. Relationships between children's CAT scores and stress scores in the developmentally appropriate class were compared to the same relationships in the developmentally inappropriate class. In the developmentally appropriate class, children who exhibited higher levels of stress during testing scored significantly lower on the CAT average, and on the reading comprehension and language portions of the CAT, than children who exhibited lower levels of stress. These findings suggest that higher levels of stress during standardized testing may negatively affect performance on the test. No significant differences between classroom type and overall test scores were found. Emphasis on academics in developmentally inappropriate classrooms did not result in higher test scores. This finding and previous research that indicates negative consequences of inappropriate curricula suggest that developmentally inappropriate instructional practices are not only potentially damaging to young children's psychological well-being, but that they are also ineffective in promoting achievement in kindergarten children. Appended are 11 references. (Author/GLR)