The ABC Quality program, South Carolina's Quality Rating and Improvement System (QRIS), is a statewide system designed to improve the quality of early care and education services. Historically, two observation instruments are used for centers that elect to participate in the state's voluntary QRIS depending on the level of quality for which they apply. One instrument is a state-developed assessment aligned to the ABC Quality standards. Administrators of the ABC Quality program would like to use their state-developed assessment across centers applying for all levels of quality. The present study investigates evidence of construct and concurrent validity of the ABC Quality observation assessment for the 0-2 year old age group. Observational data were collected simultaneously using this instrument and an established instrument to assess child care quality, the Infant Toddler Environment Rating ScaleRevised. Results suggest both instruments measure similar qualities. Furthermore, moderate to strong positive relationships were found between scores both for total scores and for subsets of item scores. Results from this investigation, coupled with the fact that the ABC Quality instrument is less time-intensive and more cost-effective to administer, lend support to inform the state's decision to move to a one assessment evaluation system for this age group.