The present invention relates to trifluoromethyloxadiazoles of the formula (I), or the N-oxides, or the agriculturally useful salts thereof; to a process for preparing compounds of the formula (I); to intermediates which are useful in the preparation of compounds of the formula (I); to the use of compounds of the formula (I) for controlling phytopathogenic fungi; to a method for combating phytopathogenic harmful fungi, which process comprises treating the fungi, the plants, the soil or seeds to be protected against fungal attack, with an effective amount of at least one compound of the formula (I), or an N-oxide, or an agriculturally acceptable salt thereof; and to agrochemical compositions comprising at least one compound of the formula (I), or an N-oxide, or an agriculturally acceptable salt thereof; and to agrochemical compositions further comprising seeds.