We study the inverse problem of recovering differential operators from spectra on compact star-type graphs when differential equations have different orders on different edges. We provide a procedure for constructing the solution of the inverse problem and prove its uniqueness.2010 Mathematics Subject Classification. Primary 34A55, 34L05, 47E05. License or copyright restrictions may apply to redistribution; see http://www.ams.org/journal-terms-of-use Licensed to Univ of Pittsburgh. Prepared on Sun Aug 2 10:59:40 EDT 2015 for download from IP 132.174.255.116. License or copyright restrictions may apply to redistribution; see http://www.ams.org/journal-terms-of-use INVERSE PROBLEM FOR DIFFERENTIAL OPERATORS 105and matching conditions for variable order differential operators on graphs [24]. Denote by Λ skμ = {λ lskμ } the eigenvalues of L skμ (counting with multiplicities). The inverse problem is formulated as follows. Fix N = 1, m.