As to the sphere of application, Article 78 CISG undoubtedly applies to interest on the purchase price. Furthermore, the provision also applies to "any other sum that is in arrears". This language has been interpreted to encompass expenses that one party had on behalf of the other as well as reimbursements when the purchase price is reduced according to Article 50 CISG. However, it is questionable whether this language also extends to claims for damages. Legal scholars seem to agree that one has a right to interest on damage claims under Article 78 if the amount in question has been liquidated vis-a-vis the other party. Whether this right to interest also applies to unliquidated sums, is controversial, however. In this study, as a result of taking into account the puspose of Article 78, we could find the fact that regardless of whether the exact amount of damages has been specified yet, the breaching party still owes compensation to the other party from the time of the breach and, accordingly, the non-breaching party should be entitled to interest payments on the loss from that time. Consequently, Article 78 applies not only to liquidated but also to unliquidated damages.