In this paper, we present cross-country evidence on firm size distribution, firm demographic and post-entry performance for 10 OECD countries. We use harmonized firm-level data drawn from business registers or social security records. These data enable international comparisons and the identification of idiosyncratic country effects. While average firm size differs across countries, due to both sectoral specialization and within-sector characteristics, we find similar degrees of firm churning across countries. In most of them, about 20% of firms enter and exit most markets every year; and about 20-40% of entering firms fail within the first 2 years of life. However, post-entry growth of successful entrants is much higher in the USA than in Europe, which may be indicative of barriers to firm growth as opposed to barriers to entry.