This article presents the results of a translation experiment investigating directionality in translation between Czech and English. A set of 80 translations (of two text types - promotional and legal -, produced by two groups of translators - translation students in the second year of their MA studies and professionals with at least 7 years of practical experience -, in two directions) was analysed to explore various aspects related to the quality of translations from and into the translators' mother tongue.
The overall quality of translations into Czech, i.e. the translators' mother tongue, was generally better than the quality of translations done in the opposite direction. Legal texts turn out to be more compatible with non-native translation than promotional texts.
A positive influence of the translators' previous experience was only observed in translations into Czech. Data on error types confirm the assumption that translation from a non- mother tongue involves more comprehension problems; stylistic errors were the most frequent type in all four sets of translations.