The objective of this study is to contribute with empirical evidence to the understanding of the determinants of export upgrading measured through two alternative indicators (export complexity level and degree of export diversification) using a cross-country panel dataset over the 1999-2013 period. For this purpose, a panel cointegration framework and two homogeneous subpanels have been considered based on the income level of the sample countries (upper-middle and high income groups, low and lower-middle income groups). Based on the Dynamic OLS (DOLS) and Fully Modified OLS (FMOLS) technique, the results indicate that export upgrading of countries is enhanced by GDP per capita, knowledge creation ( this variable is differentiated into internal knowledge(i.e human capital and research & development) and external knowledge (i.e Foreign Direct Investment and imports) and Institutional quality. The effects of these determinants vary between low, lower-middle income, upper-middle and high income country.