ENThe phenomenon of non-agreement of passive participles (mostly t-participles) is discussed on the basis of the TriMCo corpus of South-Eastern Lithuanian dialects. A quantitative analysis of the examples shows that non-agreeing t-participles appear significantly more often in East Aukštaitian than in South Aukštaitian. It is also shown that plural subjects and position of the participle before the subject increase the probability of use of the non-agreeing form. At the same time we show that (non-)agreement of passive constructions in South-Eastern Lithuanian dialects does not correlate with the semantic type of passive. We also argue that the Lithuanian dialectal constructions with non-agreeing passive participles are most probably not related to the similar constructions in East Slavic (either areally, or diachronically). The non-agreeing passive constructions are also not areally related to non-agreeing active participle constructions, but probably illustrate the same tendency for the lack of agreement with plural subjects. Keywords: Lithuanian, participles, agreement, dialectology, passive. [From the publication]