This empirical census study was a quasi-experimental analysis of certification level (primary vs. secondary) and in-field vs. out-of-field certification. The sample included chemistry teachers (n = 2312) and physics teachers (n = 1387) in New York State in 2011-12. Findings indicated that the number of out-of-field teachers was relatively low, but this masked disparities in locale and socioeconomic status, with higher incidence of out-of-field teachers in urban and high need schools. Multivariable regression analyses indicated students of out-of-field teachers did not perform as well as students of certified teachers, however, performance was not related to whether teachers had primary or secondary certification. School-level socioeconomic status was the main predictor of student performance. Implications related to equity considerations and science teacher certification policy are discussed.