U ovome se radu razmatraju postupci utvrđivanja i oporezivanja nesrazmjera dohotka i imovine kroz prizmu administrativne suradnje i pitanje tereta dokazivanja. Naime, kao i u drugim poreznim postupcima, teret dokazivanja treba biti podijeljen po kriterijima porezne pravednosti između poreznog obveznika i poreznog tijela. Prije svega, u radu će biti prikazana administrativna suradnja koja često prethodi i koja je nužna za pokretanje spomenutih postupaka, ali i kako je pandemija COVID-a 19 utjecala na takvu suradnju. Važno je na početku i definirati pojam nesrazmjera dohotka i imovine. Cilj ove analize jest istražiti pravila o teretu dokazivanja u takvim postupcima te prikazati kako se pravila o teretu dokazivanja provode u praksi. Proučit će se i praksa CJEU-a, koji je svojom interpretacijom europskih propisa donio značajne zaključke kako teret dokazivanja u poreznim postupcima treba biti raspodijeljen. Postupci utvrđivanja nesrazmjera dohotka i imovine zanimljivi su zbog svoga značaja, a taj značaj ne predstavlja broj predmeta, već u prvome redu iznos poreza koji bi trebao biti uplaćen u državni proračun. Naposljetku, u radu će se ilustrirati kako funkcioniraju odnosno kako bi trebala funkcionirati pravila o teretu dokazivanja u alternativnim načinima rješavanja poreznih sporova. This paper is considering the procedure of determination of disproportionate assets through the prism of the administative cooperation and the question of the burden of proof. Namely, as in other tax processes the burden of proof should be divided by the criteria of tax fairness between the taxpayer and the tax administration. First of all, in this work will be illustrated the administrative cooperation which often preceding and which is necessary for the initialization of the mentioned processes, but also how was the pandemic impact of COVID-19 on such cooperation. At the beginning is also important to determinate the definition of the notion of disproportionate assets. The aim of this analysis is to examine the rules on the burden of proof in such processes and to show how these rules on the burden of proof are implemented in practice. In the work also will be examined the case law of the CJEU, who with the interpretation of the EU law has adopted remarkable conclusions on how the burden of proof should be divided in tax processes. The processes of determination of disproportionate assets are interesting because of their importance, but that importance is not arising from the number of cases. The importance is visible from the amount of taxes which should be paid to the national budget. Finally, in the work will be illustrated how functionate i. e. how should function the rules on the burden of proof in the alternative tax dispute resolution.