In order to minimize tailpipe emissions of vehicles with combustion engines, highest conversion rates of exhaust gas aftertreatment systems are indispensable. At low ambient temperatures, gaseous emissions increase due to inhomogeneous mixture formation and incomplete combustion. Simultaneously, formation of condensate on exhaust gas-carrying components is stimulated due to temperatures dropping below the dew point. The acidic condensates contain more than 95 vol.-% water and a small fraction of aliphatic and aromatic hydrocarbons. In acidic environments these hydrocarbons can be polymerized, forming insoluble deposits that become progressively less reactive with time. These deposits may harm components of exhaust systems by fouling. As low temperature conditions are particularly promoting condensate formation, the aim of this study is to investigate condensate formation and composition during cold start and early warm-up phases in the exhaust duct of state-of-the-art internal combustion engines. Exhaust gas condensate of a diesel engine, a gasoline engine and a hydrogen engine (H2-ICE) is collected under various test conditions using an intensive cooler. Air- and engine coolant conditioning test benches enabling transient engine operation are used to provide realistic cold start conditions. Condensate composition and acidity is analyzed using a pH sensor, ion chromatography (IC), Karl Fischer titration, and gas chromatography coupled with mass spectrometry (GC-MS). Exhaust gas composition is analyzed using FTIR-spectrometry and a conventional exhaust gas analyzer. The correlation between condensate composition, exhaust gas composition and fuel composition is examined. Under comparable conditions, more condensate is generated in gasoline exhaust gas than in diesel exhaust gas. The investigations show a strong dependency of condensate acidity (pHcondensate,Gasoline ≈ 2 vs. pHcondensate,Diesel ≈ 3) on nitrogen oxide concentration in the exhaust gas. A calculation tool reveals that raw diesel exhaust gas generally has a lower (<41 °C) but more transient dew point temperature than raw gasoline exhaust gas (>41 °C).