This study used an embedded mixed method design to examine teachers' experiences with a state-mandated kindergarten readiness assessment during its inaugural year. Participants were 143 kindergarten teachers from one county in a Midwestern state. In general, teachers did not perceive the Kindergarten Readiness Assessment as useful for one of its intended purposes of guiding instruction. Our findings did not indicate an adversity to assessment in general. Rather, perceptions that the new KRA was less useful for practice seemed to stem from administration issues, problems with the content assessed by the KRA, and participants' misunderstandings regarding the purpose of the KRA. Furthermore, participants reported that the KRA took away valuable time needed to help students adjust to their first time in formal schooling and needed to create a classroom community. Implications for creating and implementing kindergarten readiness and other assessments as well as preparing teachers to use readiness assessments are discussed.