In the 1960s and 1970s international trade was increasingly important for employment and economic growth at the state level; however, scholarly research on the numerous issues concerning international trade and state economic activity is negligible. The present research uses a Heckscher-Ohlin-Vanek framework to examine the international trade performance of all fifty states for selected years between 1963 and 1980. A cross-section analysis generates specific conclusions concerning the determinants of manufacturing export performance at the state level. An extension of the analysis using pooled data generates specific conclusions concerning the determinants of manufacturing export performance and how these determinants changed throughout the period. Physical capital and human capital were statistically significant determinants throughout the period and the importance of these factors changed over time. The importance of physical capital decreased continuously, while the importance of human capital increased continuously.