The review of the preparatory work on the Unidroit Principles of International Commercial Contracts (PICC) demonstrates that, initially, the rules on imputation of payments were not prioritized and that it was questionable whether or not they should be introduced. One of the difficulties then encountered was the lack of comparative reference to imputation of payments in relevant international instruments, and consistent debates were carried out to shape the current version of the provisions. Although the rules on imputation of payments contained in the PICC resemble the corresponding provisions of the Draft Common Frame of Reference (DCFR), there exist some conceptual and technical differences, which are outlined in this article. In national civil codes, the policy choices in regulating imputation of payments vary, and this is, likewise, the case for jurisdictions from the present comparative research-Moldova, Romania, and Russia. The civil law codifications in these jurisdictions are representative of the Eastern European region in the context of their economic and social background. In the past years, the reforms on Civil Codes in Romania and Russia have been implemented. In Moldova, a fundamental draft law to modernize the Civil Code was recently finalized and is pending adoption. More or less, all jurisdictions have been inspired by PICC and DCFR rules in drafting the reform provisions. Imputation of payments is part of the new rules, and, in this article, we propose to briefly outline their alignment with PICC and DCFR standards. Our comparative review shows that the criteria on imputation of payments and their order of application are different in each of the jurisdictions. The rules in Romania are mostly similar to those from the PICC and the DCFR. In Moldova, the applicable criteria are partially in line with the PICC and the DCFR. In Russia, the legal framework and related case law, as developed by the highest courts, involve more particularities.