The aim of this paper is to show that the uses of quoi que ce soit are different from assertive, affirmative utterances, with the indicative mode and in an episodic context. The following parameters, which correspond to those of negative polarity or to those of free choice, are recurrent: interrogation, subordination, negation, subjunctive, non episodic context (generic for instance). Three kinds of syntactic uses are distinguished: i) quoi que ce soit is analysed in connection with the predicate of an autonomous utterance; ii) quoi que ce soit is analysed in connection with the predicate of a dependent utterance; iii) quoi que ce soit is analysed in connection with an infinitive.