The paper explores the evolution of export diversification patterns along the economic development path. Using a large database with 156 countries over 19 years at the HS6 level of disaggregation (4'991 product lines) we look for action at the intensive and extensive margins. We find a hump-shaped pattern of export diversification similar to what Imbs and Wacziarg (2003) found for production. Diversification and subsequent reconcentration take place mostly along the extensive margin whereas high income countries diversify along the intensive margin. This hump-shaped pattern is consistent with the conjecture that countries travel across diversification cones, as discussed in Schott (2003, 2004) and Xiang (2007).