AbstractSeto is an exceptional language in the Uralic family due to its systematic use of postverbal negation, although preverbal and double negation marking are also used. Postverbal negation is still the most frequent and unmarked pattern occurring in about 74% of negative clauses in Seto. This paper analyzes variation between pre- and postverbal negation in East Seto (spoken in present-day Russia), based on data gathered during fieldwork trips in 2010–2013. By applying quantitative methods that are used in variationist studies (regression modelling, conditional inference trees, and random forests), we determine the variables affecting the choice between pre- and postverbal negation. Marked preverbal negation occurs more likely with first and third person, cognition verbs, and present tense, all of which are often used in fixed expressions likeI don’t know. We also found a strong structural persistence effect in the data and remarkable differences between individual speakers.